Before your meeting starts, you can test your audio to make sure you start with the correct speaker and microphone settings. 

1) In teams, click the settings ellipses on the top right next to your initials.

2) Select Settings

3) Click Devices

4) Click the Make a test call button under the Audio Settings category

5) Microsoft Teams will run you through a testing environment, where you will record a message to test the audio input, and hear it back to test the audio output. Afterwards, you'll receive a report to view what works correctly and what does not.

If you cannot hear the Microsoft attendant speak to give you instructions, you'll need to change your speaker.

If you could hear the Microsoft attendant, but could not hear your recorded message, you'll need to change your microphone.

You can make these changes under Audio Settings