The reason why we are here is because we know that God, who is our father in heaven, has once again brought back the teachings of Jesus Christ in its fullness, and He wants you/us to have faith in Jesus Christ, repent of your/our sins, keep his commandments, be baptized into His church with proper authority and receive the Gift of the Holy Ghost. (Acts 2:36-39, 41-42; 3 Nephi 27:13-21)
Just in case you don't know who Jesus Christ or Peter is mentioned above, take a look at Matt. 16:13-18
Peter was a disciple of Christ
Christ was the Son of the living God
And who is God? Acts 17:22-31
God is our Loving Heavenly Father, and He loves us, He wants us to be happy, therefore He sent His Son Jesus Christ. (John 3:16-18)
Because of this, since the time of Adam, He has continued to call on prophets and apostles to prophesy and bear witness of Jesus Christ. (Acts 10:34-43; Jacob 7:11; Moroni 7:23)
Let's just make sure we know what Christ did.
He called and ordained the Twelve Apostles. (Luke 6:13; Mark 3:14-15)
Another words, he established an organized church for the purpose that we know who to look for salvation in unity and clarity. (Ephesians 4:11-14)
So now what? 1 Corinthians 12:28-31
We should seek the church that has apostles and prophets, and all the characteristics of the true church.
Sadly, the inevitable truth. Apostasy has occurred as foretold by the apostles. (1 Timothy 4:1-3; 2 Timothy 4:3-4; Amos 8:11-12)
However, as foretold, restoration will occur to bring back all the truth. (Acts 3:19-21; Ephesians 1:10)