The key is using Keyboard Commands.
It is easy enough to just click on the Green Box at the bottom of the screen, but I find it much faster on my MacBook Air to just use Command-Shift-S (Alt-S for Windows.)
I just finished hosting a Zoom Service for our Cedar Valley Unitarian Universalists today. Using two monitors, I had the slideshow on my separate screen and the Zoom controls on my laptop.
Making smooth transitions from pastor to slideshow and back again is important. Looking for a quick way to make the change, I referred to my Dr. Z's Zoom Keyboard Shortcuts page and found the keyboard commands for making this happen. Funny thing was that I had never used the keyboard to share my screen but it worked BEAUTIFULLY!
How do you use Keyboard Shortcuts when you use Zoom? You don't? Check my shortcuts chart and tell us which ones you use or will likely find useful.