What We Believe about Baptism
From the New Hampshire Confession of Faith:
We believe that Christian Baptism is the immersion in water of a believer, in the name of the Father, and Son, and Holy Ghost; to show forth, in a solemn and beautiful emblem, our faith in the crucified, buried, and risen Savior, with its effect in our death to sin and resurrection to a new life; that it is prerequisite to the privileges of a Church relation; and to the Lord’s Supper.
Here’s a short document called What is Baptism. (pdf)