audio problems

I use zoom to teach. I use 2 cameras : 1. for main camera, and a  2nd share camera for desktop to demonstrate drawing sketches. I use a headset to teach as well. I also want to have music while sharing the second camera. How can I do all three things at once? 

Also I have tried the share audio on;y and it does not work seems I cannot hear the music from you tube its muffled. Additionally can I share audio only as well as second camera at the same time? I have so many questions!

Anne