On the ‘Settings’ page click on User Settings/by Active to view the users in the system.
Search for users using the Search action and then open the user record by clicking on to view the details of the user. Click on the open link next to each record to open and edit that record
Under the Location(s) field set all the locations that the user belongs to and set the 'Allow Location Selection at Login' if more than one location has been specified for the user.