Once you have created the Editors groups, you can start assigning them to the users. You can assign a group to a user when adding the user as stated here or from the main group list.
1. Go to Events, and click the desired event tile
2. From the left panel, click Editors
Under the Groups column, each user will have a drop-down menu for you to select the group you would like to assign. Click anywhere in the field and select the team from the list
From the Groups field to the right, click the X next to each group's name you would like to remove for each user