Administrator access allows a user to do anything and go anywhere on the site. Administrators cannot directly see any user's pages, although they can log in as other users to do this if necessary. "Site Administrator" is the top role on the site - be careful who you trust with it!
To assign a user administrator access, select them from the list of "Potential administrators" and use the right-arrow button to move them to the "Current administrator" list. To remove administrator access from a user, select their name from the "Current administrators" list and using the left-arrow button move them back to the "Potential administrators" list.
Where there are more than 250 user accounts created on the site, you will need to search for a specific user using the search box. You can also select multiple users at once using Ctrl and Shift select and click.
There must be at least one administrator assigned to the system.