Don't make ZOOM too complicated . Here's an extract from a guide I have put together:
How to get the best out of ZOOM.
First, you will receive from the host an e-mail containing a link (in blue type usually).
Then, set your PC/Mac/Tablet/smart phone level on a firm support with the camera a little above your eye level. Set it in ‘landscape’ format.
Those watching you don’t want to see you wobbling so once placed, don’t jog your device. Don’t put it on your lap or try hand-holding it either or go walkabout with mic & vision on. Others will see & hear what you are doing.
Try having an uncluttered background behind you, certainly not showing anything moving such as another person, curtains at an open window flying, your cat or dog (cute as they may be). You can add your own background picture should you wish. See the Zoom preferences/settings appropriate to your device. Not always available with phones or tablets.
The invitation e-mail link takes care of everything - you do not need to have a Zoom account. A few minutes before the scheduled start, click on the link. You might have to wait until the host is ready.