Step 7: The Fun Begins: Screws, Washers, and more screwyness!
With the case sitting flat, fan hole in the back on the right, take note of where you need to stick these screws. the 4 holes on the left X are for your GPU, the 4 holes to the right will be for the CPU screws.
Now put the 5x15MM screws in the GPU screwholes, screwheads on the outside, so that they come into the case. Put tape over the heads to keep them from falling back out, as shown in the second photo. Now put the 5x20MM screws into the CPU screwholes, and tape them just like the GPU screws. This tape is very important, so don't take it off until I say so! Ha ha.
Lay the case flat again, and all the screws should be poking up at you, as they are in the main photo. Place 3 or 4 5MM washers on each of them, the idea being to get them level with the motherboard standoffs. Use a straightedge to check. If they come up too short or too high, the motherboard will get warped, and you won't be fixing anything.
Now the fun begins. You gotta get the motherboard back in the case, with the goal of getting the screws into those orange holes that the X-Clamp posts went through. All while you try to keep those washers on the screws! If they fall off at any point, you'll have to take the motherboard out, put them back on the screw(s), and repeat. So try not to do it, eh?
Tilt the case onto it's right side(where the hard drive connector would be), so that you can reach the screws underneath. Angle the back of the motherboard into the case, and push it all the way to the rear of the case. Lower the board until it gets held up by the rear CPU screws you installed(they should be the CPU screws if the screws were taller than the GPU screws). Now, untape one of those rear CPU screws, and point it into it's hole. Give it a few twists to hold it in place, and thread the other one in. Now, while carefully holding the motherboard and those untaped screws, lower the motherboard until more screws hold you up, and get them into their holes. Don't let those washers fall out!
When it's all said and done, you'll have screws poking through those holes. Tape the heads back to the case so they don't fall out. Now press on the motherboard around the screws, it should be solid at each screw. If not, you'll need to get back to those washers and pop another one on.
But if it's all nice and immobile, throw two washers onto each GPU screw, one onto each CPU screw, and head to the next step!