How to setup and test audio/video setting in Microsoft Teams.

Procedure

Change your default mic, speaker, or camera

To select the mic, speaker, and camera you want Teams to use for calls and meetings, select Settings and More next to your profile picture at the top of Teams and then choose Settings > Devices. 

Under Audio devices, pick the speaker and mic you want Teams to use by default. 

Under Camera, select the camera you want Teams to use, and see a preview of that camera's video. 

If you have multiple certified devices connected to your computer, you can set one as your secondary ringer, which means it'll ring when a call comes in. Answer incoming calls on any device—not just the ones that ring.
 

Make a test call

To make a test call, select Settings and More     next to your profile picture at the top of Teams and then choose Settings > Devices. 

Choose Make a test call under Audio devices. 

In a test call, you'll see how your mic, speaker, and camera are working. Follow the instructions from Test Call Bot and record a short message. The message will play back for you. After that, you'll get a summary of the test call, and you can go to your device settings to make changes.