Body
When someone calls you, you'll get a notification that lets you accept or decline the call.
-
Click Accept with audio 
to answer with audio only.
-
Click Accept with video 
to accept the call and enable video as well.
-
Click Decline call 
to decline the call and go on with your day.
You can also view a Normandale video on how to make and take calls: How to Make a Teams Call (Video 5m 8s)