L.E.D. installation Help?

I bought couple L.E.D. light bars by Pilot automotive recently. it says to connect the black wire o the chassis ground and the wite/black wire to a switched power source. What I need help with is connecting the white/black wire to the sitched power source. How do i do that? I want to connect it to my headlights.|||well, you would have to install the black to like a bolt in the car or something, the power cable tho would have to be connected to the light switch positive wire also. that's how i did it in my car (I did it to the outside door handles, and the foot well). You will want to disconnect your battery FIRST before attempting any of this. If this doesn't work then try googleing it.