In general, you want to log in with your RCS email address and your RCS password, but you can set up login accounts for other email addresses
List management
click on admin for the list you want to manage
click on manage subscribers
When entering lots of email addresses at once, click on multiple add
enter in the email address and select the "quiet" box before clicking add if you don't want to notify them that they've been added to the list
If you want to delete a user(s) from the list, click on the box in front of their name(s) and then select the quiet box if desired and click "delete selected email addresses"