One other thing I forgot to mention (I don't think I saw it in the tutorial) is. If you got your computer with a OS already installed, and didn't get the disk, you might like to know this.
If you don't like Win 10, with a clean install, you can't roll back to where you came from, from your computer ! ! ! I think there is a way around this (I didn't do this). There's a tutorial on this too, maybe you can find it here, Google it, or Youtube. You will have to download your OS to a USB Flash somehow from your hard drive or what ever you have it on, before you do your CLEAN install. Now, if you have the code from an old OS like Win7 or Win 8.1 you may be able to download it online. If you have your old disk with your old OS on it this point is moot. No matter what you do you'll need a legitimate "code" For any of this to work (this is in the tutorial).