First you must get the lower glove box out of the way by pressing in the sides of it, which will allow it to swing all the way down. Then undo the screws for the upper lid and the screws for the glove box and it should pull right out.
No problem, hope the rest of the mod goes well. I have the same exact setup with my Alpine head unit. Although I have two Ipod hookups inside my upper glove compartment, and an auxiliary input in my center consoul.