Summary:
John is baptizing many people. He then criticizes the Pharisees for their hypocritical ways. He then says that the Holy Spirt is coming to baptize with fire.

Context: Who, What, When, Where
The Message makes it clear that John is talking to the Pharisees. John is informing the Pharisees of how hypocritical they are.

Category: Baptism by John, Baptism by Holy Spirit

Conclusion:
I don't think this is proof that there is a second step to receiving the Holy Spirit. The context is also prior to the Holy Spirit existing on the earth.

Matthew 3:1-17