Add staff and set roles
Adding someone takes a name, an email and a role. Zenly works out whether they already have a login and does the right thing either way, so there is no separate account setup to chase.
Adding someone
Who can grant what
Owners and admins hand out any role. A location manager can staff their own branch with front desk and instructor, which is the point of the role: they hire the weekend receptionist without waiting for you. Only an owner can make another owner.
When someone leaves
Deactivate them. Their access to your business stops immediately while their login, which is theirs and may be in use elsewhere, is untouched. Everything they did stays attributed to them in your records. Reactivate later and their roles come back.
What each role can actually reach is spelled out in Who sees what, and where.