A team can span several levels. You join them with the Team Group Name field on each level - every level with the same name is one team group.

The rule that catches people out: for levels sharing a team group name, the Gender, Min Team Members, Max Team Members, Team Fee and Late Reg Team Fee must match exactly. If they do not, the event will not save and the message tells you which group is inconsistent.

Leave Max Team Members blank for no upper limit. Mass Update All Levels is a quick way to make the numbers match across a group.