To install QuickLook plugins, you should copy the “*.qlgenerator” file into /Library/QuickLook/ or ~/Library/QuickLook/. Note that “*” in the filename will vary based on exactly which QuickLook item you choose to install.
If a QuickLook folder is no present, feel free to create one.
After copying the file into the directory you will need to logout and then back in to your account for it to become active. Alternatively, you can prevent having to logout by running the following command in Terminal:
This will force OS X to search /Library/QuickLook and ~/Library/QuickLook for plugins and load them accordingly.