The assignment of supervisors is done by assigning individual workers to their supervisors.
In Workhub:
From your Admin portal, click on Workers, then select the worker profile from the list.
Underneath the Position option, you can click Select Supervisor. This will open a pop-up and you can select the supervisor's position and name from the drop-down.
Click Submit then Save Profile.
Now when you log in as Phil Dunphy, you'll be able to see your subordinates and their compliance from your dashboard.