Cohost or moderate a session
Test the audio and video sharing
As a cohost you are in the best position to give the presenter feedback about their screen sharing and audio quality.
Once the presenter is in the room they should share their screen. If needed, review screen sharing.
Next, they should ensure that their mic is not muted and that they can be clearly heard. If required, review audio tips.
One more way that you can give the presenter feedback through out the session is if you keep your video on. They can pin you and you can give them non-verbal feedback by smiling, nodding, and shaking your head.