Also, how to cover up cracks in your case so light doesn't shine through them.
Step 1: Choose the Color Theme
Some popular color combinations in computers right now would be black/red, black/silver/blue, black/green, silver/blue, and black/blue.
In the end, it's your choice.
Step 2: Order the Fan/s
Step 3: Install the Fan/s
I think it looks best to put it on the side panel (especially if you have a case window) because that way the whole inside of the case is lit up, and the vent will be lit up.
Or you can put it on the back of the case, or the front if you have a front fan. And some cases do have other spots.
But to install it, simply unscrew the case screws from the old fan, and take out the old fan. Then put the new fan in its place, and put the screws back in. Then plug it in to your motherboard. There should be slots that look like the ones in the pictures below.
If you have trouble identifying which slots are for fans, just look at the slots that your current case fans are plugged into.
No, you do not need to turn off your computer to plug in case fans.
Step 4: Reducing the Light Going Through Cracks in the Case
To stop light from going through undesired places, simply apply black electrical tape around that area on the inside of the case. Electrical tape will not leave anything behind, it's opaque, and so it's perfect for this job.
See the pictures
Step 5: Congrats
Also, the front part of my computer case that is lit up behind the grilles came with my computer case. Sorry guys.