Wiring Cables

I just built my first PC, my friends who’ve been helping me are currently unavailable right now. I just went to start up my computer for the first time, but everything isn’t running. My motherboard is on and glowing, but my fans on my gpu and the cooling system aren’t on and neither is my PSU...

I have just received some PoE security cameras off of Amazon, I am looking at powering them through a UniFi PoE system, I am looking at cutting the standard ends off the cameras and using a punchdown to terminate them to a cat6 cable. When I spliced the cable on the camera it only seems to use...