Baptism is an outward expression of something that has happened on the inside, that is your faith in Jesus Christ as your Savior. It is the next step after you accept God's gift of Salvation and place your trust in Jesus. Telling others that you believe in Jesus helps them see God's goodness and the difference He makes in the lives of those who choose Him.
The Bible teaches Baptism by full immersion. When you are lowered into the water you are identifying with Jesus' death and to sins control over you. Being raised up out of the water represents the way you were raised to new life just as Jesus was raised from death to life.
Let us know here if you would like to talk to someone about being baptized.