My new PC I built won't turn on

BR4ND0N

Commendable
Jan 7, 2017
5
0
1,510
Hi, I built a PC for the first time today, and nothing but the lights on my motherboard are turning on. I am not 100% sure I wired it correctly, because the manuals are terrible. For some reason, there is not a power supply 3x2 6-pin slot on my GPU. Also, what is the cable I am holding in my hand in the last picture for?

Build:
NZXT S340
ASUS B250M Plus
Intel Core i5-7500 with stock fan
2x4 8GB Crucial Ballistix Sport DDR4
Toshiba 1TB 7200RPM HDD
MSI NVIDIA GeForce GTX 1050 Ti 4GT OC (Dual Fan)
EVGA 430W PSU
TP-LINK 300Mbps Wireless N PCI-E

http://imgur.com/a/rlP3Q
 

BR4ND0N

Commendable
Jan 7, 2017
5
0
1,510

The cable is from the S340.
 

BR4ND0N

Commendable
Jan 7, 2017
5
0
1,510

I made sure it was already.