Allow access to the microphone and select one from the top-up list to add one during login.
If you need to change your microphone, you can do that anytime in settings section.
You can adjust volume and mute microphone on the left side settings.
You can also hide the camera on the left-hand side of the screen and still bring the microphone on your computer into your stream. You would just need to make sure that it shows "On Stage" as this can allow you to still talk with our community without needing to have your camera up at the same time.