Once you have created your event you can then click ADD EXISTING TEAM
Add Existing Team
Select your chosen team from the box and then click CREATE EVENT
Select Team
You will then be taken to the event page, from here if you would like to change your team select ACTIONS you can then either swap it with another existing team or edit the current participants who are involved within the fixture
Edit Participants
Move students into and out of the team by selecting the box next to their name and moving them using the arrows at the bottom of the box