Huh, that is annoying. I am trying to make this easy, so maybe I should use a ZIP or something.
When I download the file from the page here, I rename it to a .m4a (AAC) and when OSX prompts me, I say to change the file format to .m4a. Once it is a .m4a I double click it and it starts playing in iTunes.
Sorry it is not easier - I will see what I can do. The point is for it to be easy. Thanks,