I cannot hear anything

In order

1. Unmute the video itself — there is a speaker icon on the player, separate from your computer’s volume.
2. Check the tab is not muted. Right-click the browser tab; if it says Unmute site, that is it.
3. Check which output your computer is using. Headphones you are not wearing, or a monitor’s speakers, are a common culprit.
4. Refresh the page. Your attendance is not affected.

Still nothing?

Say so in the chat. If the instructor’s microphone is the problem, you will not be the only one — and we would rather hear it immediately than find out afterwards.