The fact that Peter gives orders could indicate that the baptism was done by the men who came with him from Joppa.1 Alternatively, it could simply be the case that he is the one who will do the baptizing and he is giving orders as to how it will be done. This is more likely since the task of baptizing is given to office bearers in God’s church (see Matthew 28:18–20).
48 And he commanded them to be baptized in the name of Jesus Christ. Then they asked him to remain for some days.