okay, a sound conversion utility that can't open MP3 files?

i'm obviously missing something, but i can't see for the life of me what that would be. "Preferences" is grayed out and i don't see any commands i can issue from the app's interface except "Open...".

so how do i convert an MP3 file to an AIFF? or is that not the kind of operation the developer has in mind when he calls this a "converter for multiple sound file formats"?