Surprisingly enough it’s pretty easy. Download discord for MAC. Then use invitation link from this sites menu. I don’t remember if it takes you to the guidelines channel or not. If it doesn’t then click the #guidelines channel on the left side. There is a check box you have to check to have access and agree to guidelines. I think it’s also to avoid bots but I’m not sure on that. Then switch to one of the voice channels(blender voice 1/2 or buddy hangout 1/2). In left hand or bottom of window after you join a voice chat you will see a bunch of icons. A mic to mute your mic for example. One of the icons is a monitor with an arrow in it. Click it and then select what you want to share. For example you can share just your blender window or the complete desktop.
Note: you can also do discord thru your web browser, but I’m not sure if screen sharing is available for that.
