Drop the .filter file along with all of the other .mp3 files into your Documents\My Games\Path of Exile file.

Then in Path of Exile go to options -> UI and scroll all the way to the bottom.
Click the option List of Item Filters and select the name of the filter and click save.

If you are having issues check out my YouTube channel at https://www.youtube.com/user/ShamefulPenguin for help.