I'm building my first pc and when reading the instructions its telling me to install the standoff screws that came with the case. There is 9 holes that line up between both the atx motherboard and the case and there is 3 smaller holes (2 in the middle close to each other and one that is by itself near the rear fan), these don't line up with the motherboard, is that where I would need to place these stand offs? Also should I install the cpu before or after when trying to place the motherboard into the case.