When Alma baptizes the next person he does not enter the water himself as he did with Helam. This is further confirmation that the form of baptism was required for the entrant into this new church (and certainly for the remission of sins, looking forward to the atonement) and that Alma's baptism fulfilled that requirement with his single immersion. Following his own baptism with Helam, it was no longer required for Alma to be immersed, because he had been baptized at that first instance.