If your user has administrator privileges, they will see the 'admin' page in their left navigation.
The admin page will allow you to manage three main aspects of the app - user groups, users, app config - as well as showing server logs.
The members modal will allow you add or remove users from a group; similarly, the permissions modal will give you the ability to affect which parts of the app the group member can access
From the users table you can edit details about the user - their username, email address, change their password and delete the account. You can also add a user, which includes assigning them to groups and setting the password.
The config table shows a selection of configurable items as well as database information. Typically most users will not need to affect the server defaults, and it may affect the running of the app to amend these elements; nevertheless, the app parameters can be changed here.
Logs will show server logs relating to the last day of logs - that is, starting from 0000 in the server's local timezone until the current local timezone.