a 12v dome light leer cap?

I need the help of the folks who know this stuff. I'd like to attempt to install a 12v flourescent light in my leer cap. I've never attempted any 12v wiring task before, but I've been told this is pretty easy to do myself. Here are my questions: 1) can someone supply the steps in doing this? 2) where do I pull power from? The battery or is there something else closer to the bed that is a constant 12v source for me to tap into?  3) If it comes from the battery, how do I tap in? 4) what kind of wire/supplies do I need? 5) any and all other info that I'm too stupid to know to ask is appreciated. Thanks (you can go back to laughing at me now).

Thanks for getting back to me "I Am". I was beginning to think no one wanted to help. By the way, I'm Brian. The light I wanted to add is from ebay https:////dll?ViewItem&item=320182206807. It's a 12v compact fluorescent. I don't know anything more specific than that; I assumed current and volts were the same thing. I guess that's a wrong assumption. My cap doesn't have any dome or cargo light in it now. All it has is a third  brake light that has been wired into the left tail light by a authorized Leer dealer.  My pickup has a dome light inside the cab on the headliner. I don't have a cargo light on the outside of the truck, just a third brake light. Well, what do you think? Can you help me?

Brian

Volts and amps are not the same thing.  Volts multiplied by the number of amps drawn = watts.  This is an 11 watt device.  It will pull less than 1 amp of current.  You have a couple choices, 1 run a wire to your battery and put a 3 amp fuse on it at the battery (2) run a wire to the fuse box and do the same with the fuse.  (3) depending on the make of your truck, there may be a constant wire going to the domelight.  What make and year is your truck?

Some older vehicles did have terminals to connect to ignition or constant feeds.  If you have a file or a bench grinder and a soldering iron we can easily get you to a suitable source in the fuse box.  You run the wire from the lamp to the fuse box and I will take pictures of what you need to do and post them today.  Also look for the fuse for the dome light.  It will probably be labeled dome.  there may be more than one fuse box in your vehicle.

I am e-mailing you some pictures