Editing a team switches the members of a team on either teams 1,2, and 3. Having only autobots, only decepticons, only seekers, only triple changers, only combiners, only Maximals, or only Predicons on a team gives a bonus.
to switch you must drag the characters on the bottom to the top. On the home screen you will see team 1. You can now bring your team to battle.
How to get to get to the edit area.
On the home screen, you will see you default team. Under it, you will see a icon saying, edit team. Click on it, and you will see the screen.