How to hook up ballast...

Hey, so this is going to be my first grow so all of this is new to me. I bought this 250W MH ballast from a guy on craigslist (I got a really good deal on it), and I bought a new bulb for it, but I do not know how to hook it up, I have looked on the web and can not figure it out, can someone please help me or point me in the right direction? Here is a pic of the ballast:

That looks safe

If you can't figure it out I wouldn't suggest giving it a try. Buy one that's already wired.

http://www.ebay.com/itm/250W-120V-Electronic-Ballast-/281034896530?pt=LH_DefaultDomain_0&hash=item416efc3492

I do not have the money to buy a new ballast right now and I already started germinating my seeds, so if I cant get this light working I am going to grow outdoors (I live in Florida so sunlight is not an issue), I see the ballast has 3 wires, do those 3 wires hook up to the 3 wires from an exposed extension cord?

it shows you on the ballast?

Hey it does show a wiring diagram on the ballast, however I am a little confused on how to wire it up. The ballast has 3 wires (red, black and white), it tells me:
BLK -> 120V
RED -> LAMP
WHT -> COM

Here is a picture of the ballast and the lamp socket that has a 3 prong connector, sorry for all of the confusion this is my first grow and I would like to get the ballast and bulb working as all 10 of my Bubblelicious seeds just sprouted and I put them into my propagator pro

This may help, however I have no experience with this just found a video with this tutorial;

[video=youtube;R06CHh1KyTE]http://www.youtube.com/watch?v=R06CHh1KyTE[/video]

That looks like a fire waiting to happen.