There are verious teachings and practices from many Churches on Baptism.
i)Some teach and practice baptism by immersion.
ii)Some teach and practice baptism by sprinkiling .
iii)Some teach and practice baptism by use of oil.
iv)Some teach and practice just the Holy spirit baptism.
v)Some teach and practice baptisimal class before baptising the prospect.
vi)Some teach and practice immediate baptism as the prospect is ready and willing.
vi)Some teach that baptism is not necessary as long as you have faith, they pray for you and you are saved.
1)THERE IS ONE BAPTISM:(Eph.4:5) baptism from the Greek word "baptizo" means to immense or bury.Jesus came out of the water after being baptised.(Matt. 3:16) The Ethopian Enuch went down into the water (Acts 8:36-38). These were baptism of immersion.(see also Col 2:12, Romans 3:3, Mark 1:4,5).
2)BAPTISM IS INSTANTANEOUS: (Acts 2:38, 8: :36-38, 16:31-33.) no need for baptisimal class.
3)BAPTISM IS ESSENTIAL: (I Peter 3:21, Acts 2:38, 22:16, Gal. 2:27) It now saves
4)RE-BAPTISM: (Acts 19:2-4). When Paul, the apostle found out that the brethren in Epheseus were baptized with the baptism of John which was baptism unto repentance, he asked  them to re-baptize with the baptism unto salvation which is in Jesus Christ. Baptism is a rite of passage into Christ and His body, he or she must re-baptize into the Body of Christ before he or she can be said to be accepted into the family of God's people-Church.
5)BAPTISM OF THR HOLY SPIRIT:
i) The Holy spirit  baptism was for a specific people, (Apostles and the
household of cornelius (Acts 2, Acts 10).
ii)The Holy spirit baptism was never commanded, but promised (Acts 1:8).
iii)The Holy spirit baptism could not be administered by men, but only by Jesus(Matthew 3:11-12, John 1:33).
iv)The Holy Spirit baptism was for a specific purpose, to enable the recipients to perform  miraculous signs.(Acts 1:5, 8:4, 4:31.)
v)The holy spirit baptism was for a specific mtime,during the infancy of the church.(I Cor. 13:9-10, Acts 2:1ff, Eph. 4:11-15)