Noob needs help with PSU

[jonnyblue]

hi,
building my new computer right now and have a question. my motherboard has 2 power connections(B450)

1. ATX 24pin
2. ATX 12v 8pin

my question is how do I power the 8pin?when my PSU(Cooler Master 80+ Gold MWE 750W) only has 2x cables left after using the 24pin,
both are 2x (2x 6+2 plugs), I assume one cable will go to my GPU(xt5600)which has 8pin and 6pin so one 2pin will be spare, and the other 2x 6+2 plug
would go to the ATX 12v and only one set would get used.
but here's the problem the plug key ways are all wrong.

PS yes I've looked in the manuals, they are right beside me now.

[SavageNeo]

you have 1x 24pin, 1x 4+4pin for cpu and 4x 6+2 pin for gpu what do you mean?

[jonnyblue]

Tom's H. got in first.

I guess the first thing should have been trace all the cables from the PSU to the plugs, not miss the cable stuffed in a hole.

thanks for the help. one to many Beam and colas. just turned it on, looks like no faults so far, fans and led's are running, no blinky motherboard led's.
thanks again awesome that PC guys answer so quickly.