Do you already have Virgin connected to a TV or is it being installed??
Are they sending you the stuff to do your own connecting??
Anyway, to simply connect a Virgin Media Box (I assume not V+) to your TV you can use the scart socket. Then just select the corresponding AV channel on your TV and your done.
If you connect via the standard ariel lead you will need to tune 1 channel into the Virgin. Very easy to do.
If you get the V+ box you can connect via the options above or for best results via HDMI. Same principle as the scart but with better results.