Question X570 and PSU problem: 24-pin enough or add 8pin on the top left?

[Mystos]

So I've been having this problem:
https://forums.tomshardware.com/threads/newly-built-pc-starts-no-display.3516389/

I already plugged in a 24pin cable.

But it turns out I didn't plug in a CPU cable from the PSU
There are 2 identical PSU cables labelled CPU but...

One end of these cables are split (4+4 pin) and are like this:
(round meaning cut/ bevelled edge)
round round round square
round round square round

The other non-split end, fits perfectly into the PSU.

I was told to plug in the 4+4 pin into the motherboard, but that's the end that (fits if you ignore edged/rounds and squares)

Is that fine?

There is also another 4pin (female slot on the left) right next to this 8pin I spoke of above ^
Does anything go in here?

Should I even worry about those 8pin and 4 pin connections on the top left of the motherboard?

 

[Mystos]

solved