AC power * power from your walls, is at 60Hz, 120 volts, Single Phase, has 3 wires, Black: Hot, White: Cold, Green: Ground.

You do not need to "worry" about getting the black and white cables right, but its best to do so when installing items such as switches / breakers. However the "green" wire which is ground, MUST be wired correctly if it is going to be used, and I suggest you DO use it, it can prevent some nasty tingles in your body if you were to be zapped.

If you need any help with more wiring, I will be glad to help

-Haz