What we found works best for hybrid teaching:
The best setup for hybrid involves a computer dedicated to Zoom, be it a laptop from a TA, or the professor, or the teacher station in rooms that have those. This machine will serve as the dedicated and only microphone in the room for remote students, and also the only source of audio for the students in the room to hear the remote students. This avoids feedback, and audio "bouncing". Ideally this computer is hooked into the room audio system, if there is one (which there is in most cases). HDMI is usually the way to go here if your computer has an HDMI output. Make sure you've chosen HDMI audio out in Zoom - when you plug HDMI in, it should show up as one of the options by the carat next to the Audio toggle button at the bottom left.
Test the mic on the computer you're using in the classroom. If it doesn't pick up the room well, you can request a Logitech webcam with built-in mic or just an omnidirectional microphone from Amanda (email@example.com) if you haven't already requested one. She ordered a few extras beyond what was already requested. Choose it as your input by clicking on the carat next to the audio toggle button. If you requested a webcam, you can also use it for video input by choosing it from the carat menu next to the Video toggle button in the bottom left of Zoom.
Make sure the mics and speakers on student’s individual computers for anyone in the room are OFF. A good trick to make sure this is true is tell people when they join the Zoom meeting, just don't connect to audio at the prompt. Only use your video. (They can of course also go into their settings and turn input and output volumes all the way down).
Remote students, conversely, should have their audio on, of course.
If you are concerned about remote students not being able to see the whole room, you can use a webcam and your built-in camera at the same time to get more angles on a large room, by using the Advanced tab of Share Screen and choosing "content from second camera", but it's pretty awkward - that makes a whole second window show up for the participants with that content. Another way to do it is to use a phone's camera, joining the Zoom meeting with a second account, to provide another angle, if you think it's necessary at all. One view of the room and then individual student devices for those who have them may be enough. Every situation is different!
To show video clips, use Share Screen, Basic tab, and check off "Share Computer Sound" and "Optimize Screen Share for Video Clip." Choose the window that has the video clip loaded in it, unless you actually want to share your entire desktop (Desktop 1 usually), which will show everything you do. Students in the classroom should watch the projected version of the video, not what's on their devices, if they have them, so that the audio will be in sync. (They will see an audio delay on their own computers).
Split screens are good for showing a PowerPoint and seeing everyone at once, provided you are not looking for too much detail. Only the participants can select split screen--but the instructor can if they use two devices.
You can visit Zoom video tutorials here https://support.zoom.us/hc/en-us/articles/206618765-Zoom-Video-Tutorials for specific help on any Zoom task.