When someone calls you, you'll get a notification that lets you accept or decline the call.
Select Accept with audio or the Blue Phone icon to answer with audio only.
Select Accept with video or the Blue Video icon to accept the call and enable video as well.
Select Decline call or the Red Phone icon to decline the call and go on with your day.
When a call comes in to Teams, a notification pops up, letting you know. Tap Answer or the Phone icon (the blue one!) to start talking.
When you get an incoming call, you’ll see an onscreen notification. Tap the notification to answer.