Note: the User Admin permission required to observe other Staff.
If your organization uses the Schedule feature,, go to the Dashboard -> Schedule and select the staff person you want to observe from the top. Find and click on the appointment you want to observe. Click "Observe" next the student.
You can also observe by going to "Staff"
Find the staff person you want to observe and click "Observe". Find the student they are in an online lesson with.
You will enter the online lesson as an observer. If you don't see any video initially, wait for the staff and student to join