Audio Systems: Video installation, video screens, adequate size

Question
I installed a DVD player in my 2003 Ford Explorer.  I used power source for my existing radio to power the DVD player and my FM modulator.  I also installed 4 monitors in the headrests and a video amplifyer.  I do not know how to power the video screens and the video amplifyer, they all require 12VDC.  Any suggestions?  

Answer
They should be switched from one of the ignition leads like the radio - unless it has an auto off like many fords do - after so many minutes with the key off they automatically shut off.  Find that lead and power from that, also.

The monitors should have a fuse in the line of adequate size, too.

In the worst case, if you cannot find the right power lead - or if it won't handle the current draw of the video monitors, take them directly to the battery with your own manual switch mounted under the dash or some convenient place.

Good Luck,
Cleggsan