This is how it's described in the article at scienceblogs.com:

The flute is just 8mm in diameter and has five finger holes along its 22cm length. Around each hole, there are up to four precisely carved notches, which Conard thinks were measurement markers that told the tool-maker where to chip an opening. Two deep, V-shaped notches were also carved into one end, which was presumably where its maker blew into to make sweet, prehistoric music.
Conard is working on creating a replica of the instrument, but he thinks that blowing into the instrument (without any additional mouthpiece) would have been enough. A similarly ancient swan-bone flute found elsewhere can actually be played in this way, producing four basic notes and three overtones depending on how sharply you blow. This instrument is smaller than the vulture-based model but with just three holes, it can produce a range of notes comparable to many modern flutes. Presumably the new find had an even larger range.