It's important that you don't install too many fonts in this folder, as it will cause your computer to not function as well as it should.
An easy way to organized your fonts is to make a new folder on your desktop to keep your new fonts. You can add subfolders to this folder to help you better organize your fonts. This could be alphabetically, by font family, or type of font...whichever way is easiest for you.
To use these fonts, just find the font it is that you want to use, open it and minimize it at the bottom of your screen, then it will be available to use and will show up in your fonts file in whatever program you're using.