You will have attendee controls at the bottom of your Zoom window. If you see a Join Audio icon, click it. If you have already joined audio, you will see a Mute/Unmute icon. Make sure this is unmuted.
If the above doesn’t work, make sure your computer speakers are turned up and not muted. You can also try logging out of the webinar and logging back in. You may need to restart your device if still unable to hear audio.
If still having issues, please email firstname.lastname@example.org.