Save the FacebookDiscovery installer.
A window will open asking what you want to do with a file called FDSetup.exe. Click on 'Save'.

Run the FacebookDiscovery installer.
Once the download completes click on 'Run' to start the FacebookDiscovery installer.

Follow installer instructions.
The installer will guide you through the rest of the process. Once installation is complete you can use FacebookDiscovery, congratulations!