When you are presenting, you should always do a tech check before you start. This will ensure that you are ready to go and that you don't have any technical issues during your presentation. Ideally, this happens the day before and on the day of the event. At a minimum, do one on the day of the event.
When you are ready to do the tech check, call the AV team and ask them to walk you through what to check.
Microphones - Audience can hear the presenter
Microphones - If there are multiple presenters, they should practice handing over to the next presenter smoothly
Speakers - Audience can hear the computer audio
Displays - Audience can see the presenters screen
Recording/stream - Test recording completed or stream confirmed working
Cameras - Presenter is well framed, in focus, at eye level, and camera is stable (no awkward angles, proper headroom, clean background)
Lighting - Presenter is evenly lit with no harsh shadows or backlighting (face clearly visible, no bright light behind, consistent lighting)