It is okay to add users through the Adobe admin console. If you have a lot, you can send a spreadsheet to Craig at ESUCC. If you don’t have access to the admin console, contact the ESUCC.

Attached is a sample spreadsheet formatted correctly.

To remove users you have to send Craig at ESUCC a spreadsheet that contains those users to remove. Just download a spreadsheet of all users from the admin console and remove the ones you want to keep. ESUCC also does a cleanup process quarterly that actually removes (and restores licenses) from users removed via the Admin Console, but you wouldn’t want to rely on that.