1) open the side of the PC. You can do this by simply unscrewing the side and it will slide off or it will just come off. If you're finding this hard, I'd hit youtube.

2. Now what you want to do is locate the old fan, you're going to want to unscrew the fan and take it out, be careful as you don't want to damage anything in the PC as we all know how expensive that could be.

3. Simply place the new fan into its place, plug it in and screw it up, yes its as simple as that. Now you're ready to go.