When adding or editing a staff login within Settings > Barber/Therapist Logins, you can restrict access to a specific shop if you have multiple:

Suppose John is the manager of shop 'Test Barber C' above, if his access is restricted to it, he will only be able to manage logins and see data for his shop. He can for example create a login for staff member Steve and restrict him to only see his timetable:

Restricted logins are marked with a lock icon with the restrictions listed within brackets: