I hooked up everything but I'm confused with the ATX connector.
On the board is an 8 pin port but the yellow/black 12v cable coming from the PSU is only 4 pin.
The 4 pin connector fits into the 8 pin port, but is that correct?
I also have an adaptor with 2 x 4pin power connectors at one end and a 6 pin ATX connector at the other end. This is what I used to connect my old M2N32. It ALSO fits into the 8 pin port on the Z68.
Which should I be using?
Apologies, it's been 10 years since I built a PC.
You are correct. Try it in the 4 pins that fit; line up the clip side of the connector to the clip on the motherboard; the connector only fits one way in the front or back of the 8 pin 12v port. Your board manual should also have instructions.