Three wires come out the back of the light, you don't even need to open it up.
Get an extension cord or computer power cord or cut a cord off something broken in your house as long as it is a 3 prong cord you are fine. (there are no cords available in the US that can't handle this, they wouldn't be legal or pass UL testing)
Now you cut the end of the cord off ---that doesn't plug into the wall.---
You strip 1/4" of the insulation off the ends of the 3 wires in there.
You Match the colors of the wires up with the light. They will be white to white, black to black, and green to ground (ground is a bare wire with no insulation)
You should use wire nuts that are like 5-10cents ea at true value or wherever.
The size of wire nut you need is the size they would use to hook up any other light in a house etc, so just ask the guy in that dept to pick them out for you. Say you're putting in a bigger bathroom vanity light if you want.
It is no different than any light built into your apartment or house, they are all wired exactly this same way with wire nuts. If you pulled any light off the wall or ceiling you would be able to see this.
There is zero fire hazard wiring these lights this way, they are only 150w after all. (185 tops with ballast losses)
Ir running two you could wire both together on the sam cord, still well within safe limits of any 3 prong cord, but I would advise instead that you wire each individually with wire nuts and plug them into a surge protector with all your other fans and timers and such just to be safe.
You'd have to be color blind and retarted not to be able to do this safely.
In case someone is retarted, don't do all this while the cord is plugged in. Wait to plug the cord in until after you have wired the light with wire nuts.
TAPE IS NOT REALLY SAFE IT CAN FALL OFF IF YOU DONT USE ELECTRICAL TAPE AND DO IT RIGHT
Some rare electricians like to use electrical tape over the wire nuts just to be sure they don't fall off, but if you just try to tug and pull a little on them you will know already if it might ever fall off.
This is certainly not necessary.
Another further step you could take is to just open up the light and wire it inside rather than outside the fixture so the wire nuts are hidden in there.
If any of this sounds at all complicated it won't be once you actually have the thing in your hands and you can see what I'm talking about.