Looking at your settings within Google Meet can help indicate why something isn't working.
If you are not in a meeting, you can select the Settings Icon in the shape of a cog or gear at the top right of the screen.
If you are in a meeting you can access the Settings by selecting the vertical ellipses (three dots stacked on top of each other) at the bottom right of the screen, and then select Settings.
Once in Settings, you can see where Google Meet is set to send your sound, audio, and video.
From the Settings screen you can test your speakers, your webcam, and your microphone. You can tell your microphone is detecting sound if the three dots next to the microphone change, as shown below.
If your sound is working for other programs or websites but not Google Meet, check to make sure the tab/site did not get muted.
Right click* on your Google Meet tab and make sure it says "Mute Site".
If it says 'Mute Site' that means it is currently not muted. If it says 'Unmute site', select that option and your sound should be restored.
If either your camera or microphone aren't working, one step you can take is to confirm if they are currently blocked by either Google Chrome or Google Meet.
The first step is to go to meet.google.com and click on the Settings Icon at the top of the screen (circled below in red).
Once you open your settings, the Camera Icon should appear in your browsers address bar (within the blue circle). Click on the Camera Icon.
When you click on the Camera Icon an options box should appear. Please make sure you select to always allow Google Meet to access your camera/microphone (the red circle below).
Once you select this option, hit 'Done' and your camera/microphone should be working. You can click on the Settings Icon to confirm your current settings.