Hi! :)
Baptism is like a more complete repentance. It is an outward expression of out inner repentance.
God has said that little children are clean and that they do not need baptism. So only those who are eight and older are baptized. (Moroni 8, D&C 68:27)
Just like with everything else in life, we need to follow the example that Jesus Christ himself set.
Baptism is a commandment and is required in order to live with God again.
Baptism is the first covenant we make with God. A covenant is a promise between us and our loving Father in Heaven.
He was baptized by the proper authority and by immersion. That is how baptism is done in The Church of Jesus Christ of Latter-Day Saints!
Taking the sacrament is like getting baptized again. It too is a commandment and renews the covenants that we make with God at baptism.
Faith and repentance are things that should be done every day. But we can't get baptized every day.
Instead, we take the sacrament at church.