1. Click Configuration.
2. Select the sport you wish to add a size to under the Sport drop-down menu.
3. Click Configure size charts and update system lists for Football.
4. Click Manage Size beside the size chart you wish to add the size in.
5. Type in the size you wish to add in the List Value box
6. Click Add to List.
7. Click the arrows to move sizes up and down to change the order they appear.