ModCrash's step by step guide on how to build a gaming PC
Build a Gaming PC: Prep the Case
Remove Case Side Panels
Remove both side panels from the case.
Move the cables that are in the case out of the way and remove any boxes or other goodies that are inside of the case.
Some cases these days already include the motherboard standoffs installed on the motherboard tray. If not, look for the back that has the screws that have a male and female connector. Install them in the spots marked off as the motherboard form factor you have. That would be either ATX, EATX, ITX etc.
I/O shield installation.
Install the the plate that has the same connecting ports as the back of your motherboard. This is called the I/O (input/output) shield. The I/O shield helps protect your motherboard from dust and accidentally placing things like cables and fingers where they don’t belong.