How to see all participants while presenting or sharing screen on Mac air

I can not see the participants while I'm screen sharing or presenting. I couldn't find the meeting control bar on my screen. When I click the "more" with three dots it only shows one option but not the video panel. Please see the screenshot attached. I researched and tried many different ways but still can not find the video panel anywhere on my screen. I really need help. Did anyone have similar problem and could anyone advise? Thank you so much!