Can you post the whole motherboard pic with the setup you have done.
The latch should match with the wedge on the 2x2 power slot.
^^
Great you solved it. Remember when ever you connect these type of connectors match the "square" and "round" notches. Will never go wrong.
Use RealTEMP and CoreTEMP to report temperatures.
You are fine. No worries.
Nice, that your problem got solved.
But, my suggestion would be you should not attempt to assemble a computer unless you are fully aware of what you are doing.