Tell me how to make it work !!!

OK, for $3,99 it could need a slight install explenation, don't you?
Just bought the app from the Apple store, where they say it needs "iBirdRemoteXXX.xpi" installed on the (Windows?) computer to work, thay give a website: http://addons.songbirdnest.com/addon/... and what do I find here?
Nothing, but to have Bonjour installed. Of course, nothing works, spent the buck for nothing and don't know how to use it.
Why programmers ALWAYS think that everybody is a freak and should be able to make IT stuff work. Don't worry, at Apple they have such problems too (took me 2 weeks before AirportExpress worked), but at least there was a step by step instruction.