Asigning values to button via XLM

Hi i’m building an xml mp3 player with the tutorials in this valuable forum, is all good but i want to have a button that when pushed, downloads the zipped mp3 file of what you are hearing. (the mp3 and zip version are in same directory) the file that this button points to changes according to the new item in the xml that also changes the song you are listening. Is this hard to do?
hank youC:-)