By now I assume you have purchased the components you'll need to assemble your computer and you either have a bunch of boxes unopenned, or you've openned everything, and are not sure where everything goes.
The first thing you should do is to get out your computer assembly tools, and set aside a working area to build your computer. This could be an area of the floor, or a table. This may or may not take you a couple of days depending on the time you have, so it should be an area where the kids or other people will not be picking up parts and moving them from one spot to another. You don't want the kids playing with the parts. It should be a spot where you have access to a power receptacle or power strip. Gather all the components together in your work area and let's get started.
Open up the computer case box. Remove the computer case from the carton. Remove the protective cover. Put the boxes and packing material out by the trash, unless your planning to ship the computer to somewhere when your done.
We now have a nice and shiny new computer case. The first thing we want to do is remove the both sides of the computer case. They are held on the case by four or six thumbscrews on the back of the case. Remove the screws and slide the covers backwards to remove them. They should be a little tight, apply consistent pressure and they will slide back. On most cases the covers are aluminum, they will bend and scratch easily. Put them in an out of the way place where no one will trip over them. We will not need them until the computer is completely assembled. Put the four or six screws right next to the panels. That way you won't lose them, and you'll know exactly what there used for a couple of days from now.
You should find a bag of screws, and an instruction booklet. The instruction booklet will be referred to as we start assembly of the components in the case. Set it aside for now, and look at the bag full of screws.
Look through the screws for the cooper stand offs. These are screws with a screw hole in the top of the screw. There should be nine of them. They are used to raise the motherboard slightly away from the case, and ground the motherboard to the case. The ATX motherboard has nine holes in the motherboard. The motherboard will rest on top of the stand offs, and other screws will go through the motherboard and screw into the top of the stand off posts to secure the motherboard to the case.
For now all we want to do is screw the nine copper stand offs into the tray inside the case in the holes provided. There are more than nine holes in the case. The holes you need should be stamped with an "A" or some markings. On the Gigabyte cases they are marked A1 through A9. Screw the posts in tight, but not super tight.
When done, put the case aside, put the bag of screws inside the case with the instruction booklet. We won't come back to the case until we get the motherboard ready.