Step 9:
Motherboard Installation

Before motherboard (mobo) installation the processor (CPU), heatsink, and RAM memory should all be installed onto the mobo. In other words, don't skip anything.

Now the mobo can be installed into the case. The mobo is very sensitive so handle the mobo very gently.

Read through the instructions before you begin, then follow them point by point as you install the board.

Let’s begin:

Ground yourself.
All motherboards have lots of holes in order to have at least some holes that line-up to the holes in any one case or mounting plate. Select which holes you will use for attaching the board. You can hold the board above the case (mounting plate) and visualize which holes on the board match holes in the case (mounting plate), or by whatever method that allows you to line up a suitable number of matched holes.
Locate your 'spacer screws'. Screw them into the holes you selected in the case or on the mounting plate. Tighten them. Some cases come with small plastic spacers that will snap into the selected holes.
On some cases there may be one or two eyelet holes (long holes in the case that allows things to slide in it). If you have the eyelet holes, you would also have plastic standoffs. Install the plastic standoffs on the mobo opposite the eyelet holes. They should poke through the mobo and expand to keep them in place. The little disk on the other end will later be used to slide into the eyelet holes.
Slide the board into the case. Make sure it sits on the spacers and that the spacer holes line up. If you have eyelet hole standoffs, make sure the little disks are placed into the wide end of the eyelet hole, then slide over to the narrow part, this should lock them in. Once this is done all the spacers should line up.
If you have a case with a detachable mobo mounting plate, you will need to make sure the I/O connectors (Parallel, keyboard, and mouse ports) face to the back. They need to align and go through the holes in the back of the case. Some cases may have a covering on the holes. If a thin plastic plate is there, poke through it. If a metal covering is there, take a flathead screw driver and pry the metal covers off.

When complete, you should have the motherboard sitting in your case, with screw holes lined up with the spacers beneath, and the I/O connectors sticking out the back holes.
With one screw hole at a time, take a screw and a plastic washer, and screw down the board to the spacer screw beneath the board. It’s important to use plastic washers in order to prevent grounding the entire board. Tighten all the screws snug, but not very tight. You don’t want to crack the board! However, the board should not wiggle when you’re done.
If you have a case with a removable mounting plate, it’s now time to install the plate back into the case.

If the plate is installed from the side or from the rear, insert the bottom edge of the plate into a guide rail on the bottom of the case, then rotate upward. The top edge of the plate will contact the case. Then you can screw it in, or a spring loaded handle will lock it in.
Inspect your handiwork. Be sure the board is tightly secured and that it doesn’t touch the case or the mounting plate. The slots and connectors should line up in the back of the case.