If the event has team groups, you are taken to Select Teams and Team Members after choosing your athletes.

Add a team, name it, and tick the athletes who are on it. The team fee is added on top of the individual entry fees. Some events allow more than one team per group; some set minimum and maximum team sizes, and you will be told if your team is outside them.

An athlete has to be entered individually before they can be put on a team.

On a meet sanctioned by USA Gymnastics, teams are still built here in MeetMaker rather than at USA Gymnastics - but process your reservation first, so the athletes exist on the entry, and then add the team. There is an Add New Team button on the reservation page for this, and it is also how you make a team entry when you have no individual athletes to add.