Typically, teams are built based on what positions you have been assigned to. For example, all 1st grade Sunday School teachers, 2nd grade SS teachers, 3rd grade SS teachers, 4th grade SS teachers, and 5th grade SS teachers might make up the "Elementary School Sunday School Teachers" team. It is much easier to just assign the volunteer to one of these positions and then have them automatically appear in the Sunday School teachers team, than to have to assign them to both the position AND the team.