Everything will fit behind the stereo, loads of space. I fitted mine to the same radio that you have. Just plug in the plug and then unscrew one of the screws on the back of the radio to connect the ground wire job done.
For aux playback just plug in the aux cable and start playing music press CD on the radio and you will hear sound.
For USB play back you can only have 6 folders of 99 songs in each folder. just press CD and then use 1-6 on radio to select folder in usb device.
I have just dropped cables down to the tray and can pull out extra cable if needed. I currently use the USB playback the most and have fed all the cable slack up into the void behind the radio. The unit is nice and tidy and there is no cable rattle.
Hardest part of the instal is getting the blasted radio out, after that it took 2 mins to install and refit everything. One you have the radio and bottom cubby out you will see all the free space.