The first step is to download the latest version of the Adafruit Fritzing Library from GitHub
The easiest way to do that is to click that big nice button up there, otherwise you can also go to the GitHub repository and manually download or clone.

Next, open the archive and extract the file "AdaFruit.fzbz" to a convenient spot (I use the Desktop). After you import the library to Fritzing and save it, it will copy over all the necessary files to your Fritzing user directory, and you'll be able to delete the FZBZ file from wherever you extracted it.

The next step is to import the library into Fritzing...