Welcome to the forum, gryphon! Let's see if we can get you up and running.
The first thing that I'd check is whether or not the video conversion feature is set to "ON" (which should be the default). How to do that starts near the bottom of page 72 in the manual under the "Setting the Video options" section. The menu option is the first one on page 73, "V. CONV". You want that to be set to "ON", at least initially.
There is also a note on the bottom of page 15 (the page that shows the video conversion diagram) that reads:
"1 • If the video signal does not appear on your TV or flat panel TV, try adjusting the resolution settings on your component or display. Note that some components (such as video game units) have resolutions that may not be converted. In this case, try switching Digital Video Conversion (in Setting the Video options on page 72) OFF."
Just some things to get you started, if you haven't tried those already. Please let us know if that works, and if not, we'll keep trying!
Adam