You need to open and then remove the screws securing the lower glove box first and swing that down to gain access to the bolts securing the top glovebox lid hinges, I kind of rememebr also having to remove some trim at the bottom of the larger glovebox near the door frame to gain access to additional bolts, but it's been a while so maybe I'm a little confused on thius one, however bear this in mind should you not be able to pull down the lower glove box.
Remove the bolts / screws securing the upper glove box lid hinges, and remove the upper glove box lid completely (again sorry for being vague, I can't remember if there is additional screws securing the facia or not at the top) if there is remove these also, if not the fascia simply pulls off revealing the mounting brackets for the CD changer.
Remove the screws securing the mounting brackets and the CD changer simply slides out, disconnect the white plug from the rear to completely remove it from the car.
pretty simple really, just take your time so as not to damage any trim