To learn means you must step forth into the completeness of what God has for you. You must do things on your own and possibly even teach others. The writer of this passage of scripture has told us to move toward maturity and toward growth through the act of repentance, and stepping out in faith. Once we have repented of our transgressions, we must then begin trusting in our faith that God is real and will do what He says he will do. We must begin to walk in the rest of the principles of Christ.
Baptism is the act of cleansing or purifying someone.
It is a total covering or immersing of an individual with a fluid or with something of a cleansing nature. Many believe this refers only to an immersing of the body under water, but it refers to a baptism or immersing of the person with water or with the Spirit of Christ. Therefore, we are baptized and then we are to move forward. John said to be baptized in water, this was a total immersion in water, and then there would come the baptism of the Holy Spirit, this would be an infilling of a cleansing entity, the Holy Spirit. So with baptism as John speaks of, we have a total covering or cleansing in water, and the other baptism is a purification of the inner person, by the total coverage or infilling cleansing of the Holy Spirit.