@ahnfire I’m trying to work out the same thing. I’ve got the ATXRaspi, the CTP 12v to 5v 3A converter , the momentary switch, a 12v 6A supply and the 12.1" display board driver card. I m just waiting on displaysscreens.com to ship me a replacement LTN121XL01-N03 SAMSUNG 12.1" 1024×768 screen (the first one got damaged in shipping :-( )
I answered my own question by looking at the original post I can see how he added the 12VDC switch in front of the display board and the CPT.