Under the Roles tab will list all of the known user roles and the users that are in each role.
Current sessions shows the current user sessions. The sessions are stored in the database and persist over time. You can delete a session.
When creating a user specify a user id, their name, whether they are an administrator, their email address and an initial password. Note: if a user is created as an administrator then they will have full access to do anything on the RAMADDA server.
The Home Folder allows you to specify an existing folder, under which a new folder with the user's name will be created. This folder will be owned by the user (so they can upload files, etc) and is added to the user's list of favorites. You cannot actually type in the field. Rather, press the Select link to popup a folder selector.
If you have configured RAMADDA with a SMTP mail server then you can also send mail to the new user, including instructions on how to change their password. Just select the "Send an email to the new user with message" checkbox.