the green plug I have isn't in the pdf file
Green is serial port. Not for video. You would need to buy a video card. You could use the video card you buy for the main and he integrated one for the extended monitor.
Gen. Nick - All accurate information. Probably better to use pictures to describe plugs but you offered useful info. *pats on back*
what would I go about using the green for?
squeelAnother tip: Most high-end graphics cards (i.e. 9800GTs, GTX 260, etc.) have two DVI-I ports instead of VGA and DVI-I. They all have S-Video but no one really uses S-Video for monitors, only for like TVs usually.
It's not s-video. It's a multifunction port. If you look, it has more contacts than the 4 that s-video has. Mine came with a component out adaptor cable.