First we must realize that because of the fall of Adam and Eve, all mankind is in a fallen and lost state. We commit sin and not one of us can avoid that. In this fallen state we are unable to return to God's presence, which is why we are "lost." For this reason, God has lovingly provided a way to overcome our fallen state. He provided a Savior for us, who of course is Jesus Christ. His perfect atonement (sacrifice for us) allows us to become clean and perfected in him if we follow his gospel by having faith in Him, repenting, and being baptized (Alma 34:8-15). So I guess we can classify that as one purpose for us during this life: follow Christ's gospel so we can return to God and be saved.
To put this one more way, in terms of mercy and justice, the atonement provides mercy, which can "satisfy the demands of justice." So, "he that exercises no faith unto repentance is exposed to the whole law of the demands of justice; therefore only unto him that has faith unto repentance is brought about the great and eternal plan of redemption" (Alma 34:16).
Where do we start? Amulek says, "cry unto him for mercy; for he is mighty to save. Yea, humble yourselves, and continue in prayer unto him" (Alma 34:18-19). The first step is to pray to God in humility asking for his help and his mercy. I'd even suggest meeting with missionaries; in fact, Amulek was a missionary when he taught this lesson! Click here to contact the missionaries in your area.
Amulek gives a big warning to the people he teaches. He tells them: "If ye turn away the needy, and the naked, and visit not the sick and afflicted, and import of your substance, if ye have, to those who stand in need- I say unto you, if ye do not any of these things, behold, your prayer is vain and availeth you nothing..."(Alma 34:28). So more is required of us than just faith and repentance, we must use our means in this life to help those less fortunate than ourselves.
The next point Amulek makes is also with very strong language that I won't paraphrase because that would only take away from it. He warns us against procrastinating our day of repentance:
"32 For behold, this life is the time for men to prepare to meet God; yea, behold the day of this life is the day for men to perform their labors.Some more counsel on how to live our lives to fulfill our purpose here (Alma 34:38-40):
33 And now, as I said unto you before, as ye have had so many witnesses, therefore, I beseech of you that ye do not procrastinate the day of your repentance until the end; for after this day of life, which is given us to prepare for eternity, behold, if we do not improve our time while in this life, then cometh the night of darkness wherein there can be no labor performed.
34 Ye cannot say, when ye are brought to that awful crisis, that I will repent, that I will return to my God. Nay, ye cannot say this; for that same spirit which doth possess your bodies at the time that ye go out of this life, that same spirit will have power to possess your body in that eternal world.
35 For behold, if ye have procrastinated the day of your repentance even until death, behold, ye have become subjected to the spirit of the devil, and he doth seal you his; therefore, the Spirit of the Lord hath withdrawn from you, and hath no place in you, and the devil hath all power over you; and this is the final state of the wicked." (Alma 34:32-35)
- "Humble yourself"
- "Take upon you the name of Christ" (you do this through repentance and baptism)
- "Worship God," regardless of where you are
- "Live in thanksgiving daily"
- "Be watchful unto prayer continually, that ye may not be led away by the temptations of the devil"
- "Bear with all manner of afflictions" (patiently endure trials)