The mp3 version of this music represents the "finished" product, adding keyboard input to accompaniment, unless it is a keyboard solo. Click the Play/Download mp3 File link. This will begin to play the file in Media Player or the default player you have configured. If you wish to save the file to your hard drive, right click the same link and select the Save As option and you will be given a choice of a directory on your computer to save the file.
When you navigate to the directory where your file is saved, you will find the downloaded file with a .mp3 extension. Double clicking on this file will bring up the default media player in your computer and you can listen to the file. Like any file, it can be played in another program or sent to an external player, or to internal or external storage.