If you are connected to the AV System, and what’s shown on the projection screen does not match what is showing on your computer, here’s what to do if you are using an Apple Laptop with function row keys.

So you only need to press two keys: Command and F1. The command key is right next to the space bar, and the F1 key which is on the far upper left side of your keyboard. Press those two keys at the same time,
And the Projection Screen should mirror what’s on your desktop. If you want to toggle back to the extended display, simply press command and F1 at the same time before and you’ll toggle back to that.
To proceed with the tutorial, press the “Projector Mute” button on the Touch Panel.