Next, you'll assemble the case. You'll need to install the power supply, the motherboard, a faceplate and standoffs to hold the motherboard in place. You'll also need to connect some wires to the motherboard.
Your motherboard should have come with a face plate for its back connectors. The case already has a hole cut in it for the plate, so you just need to put in the plate and press it until it clicks into place. Now you can put in the motherboard. It needs to sit about a quarter of an inch (6.4 millimeters) away from the case's surface so that none of its connectors touch the case. You'll accomplish this by placing spacers, which are also included with the motherboard.
Because each motherboard is different, you'll have to set it into the case first to see which screw holes on the motherboard match up with the pre-drilled holes in the case. Then you can take the motherboard back out, place the spacers, and put the motherboard in on top of them. Make sure that the motherboard lines up with the faceplate and the holes line up with the spacers.
Find the screws that fit (these should have come with the case) the spacers and screw down the motherboard. Don't screw them in too tightly -- they just need to be snug. Be very careful when putting in the screws. If you drop them into the case, they could damage the fine wires on the motherboard.
Now you can install the power supply in the case if it's not already installed. The power supply has two sides. The fan side faces outside the case and the wire side faces inside. Slide the power supply onto its brackets and secure it with screws (the case or the power supply should have come with them).
Connect the power leads to the motherboard. There should be a large one and a small one, and it will be obvious as to where each one goes.
You'll be left with about 15 more wires. Don't worry -- the manual has a page to tell you exactly where each one goes. Each of them has a label that corresponds to a label on the correct port.