Staff access allows a user to create controlled groups.
To assign a user staff access, select them from the list of "Potential staff" and use the right-arrow button to move them to the "Current staff" list. To remove staff access from a user, select their name from the "Current staff" list and using the left-arrow button move them back to the "Potential staff" 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.