What is my purpose? Why do you believe we exist?
The Book of Mormon teaches us: Adam fell that men might be; and men are, that they might have joy.
Read all about it here.
“Adam fell” is referring to the expulsion from the Garden of Eden. When he and Eve ate the fruit, it was an act of disobedience and they were cast out of God’s presence. But it was a necessary act – for they were then able to have children.
Elder Russell M. Nelson of the Quorum of the Twelve Apostles explained why the Fall was necessary:So Adam fell that men might be … and we exist so we might have joy.
“The Creation culminated with Adam and Eve in the Garden of Eden. They were created in the image of God, with bodies of flesh and bone. Created in the image of God and not yet mortal, they could not grow old and die. ‘And they would have had no children’ [2 Nephi 2:23] nor experienced the trials of life. . . . The creation of Adam and Eve was a paradisiacal creation, one that required a significant change before they could fulfill the commandment to have children and thus provide earthly bodies for premortal spirit sons and daughters of God.
“. . . The Fall of Adam (and Eve) constituted the mortal creation and brought about the required changes in their bodies, including the circulation of blood and other modifications as well. They were now able to have children. They and their posterity also became subject to injury, disease, and death”. 
JOY is a word I have always wondered about – it seems too high and glorious to comprehend or explain. But thankfully, the scripture continues on the subject:
And the Messiah cometh in the fullness of time, that he may redeem the children of men from the fall. And because that they are redeemed from the fall they have become free forever, knowing good from evil; to act for themselves and not to be acted upon, save it be by the punishment of the law at the great and last day, according to the commandments which God have given.
Wherefore, men are free according to the flesh; and all things are given them which are expedient unto man. And they are free to choose liberty and eternal life, through the great Mediator of all men, or to choose captivity and death, according to the captivity and power of the devil; for he seeketh that all men might be miserable like unto himself. (2 Nephi 2:25-27)
This scripture from the Book of Mormon is key in understanding how the Fall affected (blessed) us, and how we are capable of experiencing joy. Adam and Eve’s posterity were likewise banished from the physical presence of God, but we are all innocent from the original sin because we had no part in it. “It was therefore unfair for all of humanity to suffer eternally for the transgressions of our first parents, Adam and Eve. It became necessary to settle this injustice; hence the need for the atoning sacrifice of Jesus in His role as the Savior and Redeemer”.  It is possible of every soul to obtain forgiveness of sins – to have them washed away and be forgotten! The transcendent act of the Atonement saves us from the fall, and we are free to know the joy of our redemption, to know good from evil, and to act for ourselves. And to have kids.
Do you believe we are saved by grace?
Grace refers to the divine help or strength given to us through the bounteous mercy and love of Jesus Christ. The grace of Jesus is made possible by his atoning sacrifice, enabling mankind to be raised in immortality, receiving his body from the grave in a condition of everlasting life.
It is also through the grace of the Lord Jesus Christ that we may receive strength and help to do the good that we cannot on our own. It is an enabling power that allows us to “lay hold on eternal life and exaltation after [we] have expended [our] own best efforts”. 
This is what the Book of Mormon prophet Nephi meant when he said: For we labor diligently to write, to persuade our children, and also our brethren, to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do. (2 Nephi 25:23)
It is truly the grace of Jesus Christ that makes salvation possible. This principle is expressed in Jesus’ parable of the vine and the branches (John 15:1–11). But grace “cannot suffice without total effort on [our] part” – hence Nephi explaining we will be saved by the grace of Christ after all we can do.
“Some Christians accuse Latter-day Saints . . . of denying the grace of God through claiming they can earn their own salvation. We answer this accusation with the words of two Book of Mormon prophets. Nephi taught, ‘For we labor diligently . . . to persuade our children . . . to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do’ (2 Nephi 25:23). And what is ‘all we can do’? It surely includes repentance (see Alma 24:11) and baptism, keeping the commandments, and enduring to the end. Moroni pleaded, ‘Yea, come unto Christ, and be perfected in him, and deny yourselves of all ungodliness; and if ye shall deny yourselves of all ungodliness, and love God with all your might, mind and strength, then is his grace sufficient for you, that by his grace ye may be perfect in Christ’ (Moroni 10:32).
“We are not saved in our sins, as by being unconditionally saved through confessing Christ and then, inevitably, committing sins in our remaining lives (see Alma 11:36–37). We are saved from our sins (see Helaman 5:10) by a weekly renewal of our repentance and cleansing through the grace of God and His blessed plan of salvation (see 3 Nephi 9:20–22).” 
What happens to us when we die?
Rather than a short form answer, which may very well raise further questions, I want to answer this as comprehensively as my little bloggy can go.
Both the Book of Mormon and the Bible are pretty clear that we lived with God before we were born. The Bible refers a lot to people being chosen and ordained prior to being born on Earth (see Ephesians 1:3-4 and Jeremiah 1:5, where prophets were comforted, knowing God knew them before they were born).
And good old Job was not only told he was around when God laid the foundations of the earth, but that we all shouted for joy when the creation was planned and done! (Job 38:4-7)
And clearly for Satan and his minions to be cast out of heaven into the earth, we all had to be in that heaven to begin with. (Revelation 12:9)
The Book of Mormon refers to our pre-mortal life in more detail:
And this is the manner after which they were ordained—being called and prepared from the foundation of the world according to the foreknowledge of God, on account of their exceeding faith and good works; in the first place being left to choose good or evil; therefore they having chosen good, and exercising exceedingly great faith, are called with a holy calling, yea, with that holy calling which was prepared with, and according to, a preparatory redemption for such. (Alma 13:3)
This is such a wonderful piece of knowledge! You must read about it here.
So we know we lived in heaven a long time ago. And that our Heavenly Father created a plan for us all to live on Earth, have experience and joy, be tried and tested, and to be given the choice of returning to Him.
The scriptures are also clear we will live after we die.
We know that when we die, our body and spirit separates. Where our spirit goes is another great question (go on, ask me ...). But the atonement of Jesus Christ conquered death, making it possible for us to be resurrected after death. Woo! AND such resurrection is a free gift to all! Double woo!
This is what the prophet Alma is talking about here:
Now, concerning the state of the soul between death and the resurrection—Behold, it has been made known unto me by an angel, that the spirits of all men, as soon as they are departed from this mortal body, yea, the spirits of all men, whether they be good or evil, are taken home to that God who gave them life.
The soul shall be restored to the body, and the body to the soul; yea, and every limb and joint shall be restored to its body; yea, even a hair of the head shall not be lost; but all things shall be restored to their proper and perfect frame.
What a happy thought for the disabled, the handicap, the bald.
The prophet Alma then goes on to explain the relationship between our lives on earth and where we end up afterwards:
And then shall it come to pass, that the spirits of those who are righteous are received into a state of happiness, which is called paradise, a state of rest, a state of peace, where they shall rest from all their troubles and from all care, and sorrow.
And then shall it come to pass, that the spirits of the wicked, yea, who are evil—for behold, they have no part nor portion of the Spirit of the Lord; for behold, they chose evil works rather than good; therefore the spirit of the devil did enter into them, and take possession of their house—and these shall be cast out into outer darkness; there shall be weeping, and wailing, and gnashing of teeth, and this because of their own iniquity, being led captive by the will of the devil. (Alma 40:11-13,23)
This is another sound example of how the Book of Mormon helps us to understand what we already know from the Bible, and in greater (perhaps even simpler?) detail. Do you agree?
Note: I’ve tried to make this answer as simple as possible. I’m sure it raises further questions and thoughts, for example I’ve totally skipped over the Judgment part and Christ’s role as our mediator in determining ‘were we end up afterwards’.
But know this: we existed before this life, and we will continue to exist after it.
We are currently in Act II of a 3-part play.
“The assurance of resurrection gives us the strength and perspective to endure the mortal challenges faced by each of us and by those we love, such things as the physical, mental, or emotional deficiencies we bring with us at birth or acquire during mortal life. Because of the resurrection, we know that these mortal deficiencies are only temporary!” 
Why was Christ baptised?
Jesus Christ is the perfect example. Being holy and without sin, Christ physically showed us how to be baptised and why. What an example of humility and obedience – for that is what it was; an act of obedience.
Although Jesus Christ was baptised by John the Baptist far away from the Americas, the people there knew this event was taking place. Prophets taught (and recorded in the Book of Mormon) the people of baptism, and carefully taught why their Saviour would do so:
Wherefore, I would that ye should remember that I have spoken unto you concerning that prophet which the Lord showed unto me, that should baptize the Lamb of God, which should take away the sins of the world.
And now, if the Lamb of God, he being holy, should have need to be baptized by water, to fulfil all righteousness, O then, how much more need have we, being unholy, to be baptized, yea, even by water!
And now, I would ask of you, my beloved brethren, wherein the Lamb of God did fulfil all righteousness in being baptized by water?
Know ye not hat he was holy? But notwithstanding he being holy, he showeth unto the children of men that, according to the flesh he humbleth himself before the Father, and witnesseth unto the Father that he would be obedient unto him in keeping his commandments.
Wherefore, after he was baptized with water the Holy Ghost descended upon him in the form of a dove.
And again, it showeth unto the children of men the straitness of the path, and the narrowness of the gate, by which they should enter, he having set the example before them. (2 Nephi 31:4-9)
We believe that “entering into the kingdom of God is so important that Jesus was baptized to show us ‘the straitness of the path, and the narrowness of the gate, by which [we] should enter’ (2 Nephi 31:9).” 
“Born of a mortal mother, Jesus was baptized to fulfil His Father’s commandment that sons and daughters of God should be baptized. He set the example for all of us to humble ourselves before our Heavenly Father. We are all welcome to come into the waters of baptism. He was baptized to witness to His Father that He would be obedient in keeping His commandments. He was baptized to show us that we should receive the gift of the Holy Ghost.
“As we follow the example of Jesus, we, too, demonstrate that we will repent and be obedient in keeping the commandments of our Father in Heaven. We humble ourselves with a broken heart and a contrite spirit as we recognize our sins and seek forgiveness of our trespasses (see 3 Nephi 9:20). We covenant that we are willing to take upon ourselves the name of Jesus Christ and always remember Him” 
Good thing the Book of Mormon expands upon this subject, as the Bible isn’t quite as clear …
Why is the atonement necessary?
Do you believe we are accountable for our choices or actions, and to what extent?
These are big topics, but the Book of Mormon can answer these questions too.
I’ll show you soon …
Can you see just how useful companion scripture can be? The Bible and the Book of Mormon go hand in hand. Once we have a testimony that they are both indeed the word of God, we can then dive into the life and teachings of our Saviour, Jesus Christ. I love reading the scriptures! I love the happiness I feel when I understand something more fully, the enlightenment I feel and the peaceful assurance that brings.
If you wish to order a free copy, let me know or click here.
Feel free to read or listen to it here.
 Russel M. Nelson, Ensign, Nov. 1996, 33
 James E. Faust, Ensign, Nov. 1988, 12
 Bible Dictionary, “Grace,” 697
 Dallin H. Oaks, Ensign, May 1998, 56 - bold & underline added
 Dallin H. Oaks, Ensign, May 2000, 14
 Robert D. Hales, Ensign, Nov. 2000, 7–8