Thank you for adding more description.
In that setting, the simplest way of doing the camera is to use a good quality webcam. This would have some zoom capability and also the fitting for attaching to the tripod. You would need to get an extra-long USB cable to connect the webcam to the computer, which would need to be within 10ft or so. The webcam is plugged into the USB port of the computer with Zoom and Zoom gets the image from that. There's no separate app.
As for getting the sound from the room's PA, that really depends on what's available from that PA system. The best way is if you can get a direct feed from it, and then that is connected to a "USB audio interface" which converts the sound from the PA into a signal the computer and Zoom can understand. This probably needs some outside help in your case.
I hope you can get some advice from knowledgeable person near you as there might be several new items and concepts here. But, once you do it once, you'll be able to carry on.
The likely basic pieces are:
good quality webcam
10ft. USB cable (suitable for the webcam and computer)
tripod
audio cable from PA to computer table
USB audio interface