This is a reference diagram I drew in order to remember the setup that worked for projecting from the Cintiq tablet while I drew on it. The VGA Distribution Amplifier (DA) is the key that makes the whole thing work. Ususally the AV folks can provide one.
Also, I just realized the USB cable goes from the Cintiq’s “box” to the laptop, not from the Cintiq itself as it appears here.