Display Settings

If you want to use the whiteboard as a second screen, maybe to play a video, while you are free to do something else on your laptop screen, just press:

Command + F1

Just press Command+F1 again to switch back to one screen, this is called mirroring your display...

If your screen looks ... wrong, it's probably the screen size settings, gain you can change these quickly by pressing:

Option + F1

From there you can tweak the numbers, hold down the option key and press Scaled for more options. You probably want a size like 1280x768 or so.