Yes your right, you have to remove the top lip. A piece clips out from underneath to reveal 2 screws. Once screws have been removed you can remove the second part of the lip.
The OE stereo is held in with two more screws. One is definately on the top left corner of the stereo.
Once removed the stereo should pop straight out.
To remove glovebox, first open it. remove the matting, or push towards the rear to reveal 3 torx screws on the floor and 4 on the roof of the inside of the glovebox.
Remove all 7 screws and the glovebox should slide out towards you ready for you to fit the changer.
Remember to diconnect the glovebox lamp as you wont get the glovebox out very far.
Feed wiring into centre console, connect together (as you have a new connection to the stereo (i take it your fitting manufacturer's changer) and route the changer lead into the glovebox.
Then reverse most of the above procedures to refit.
Hope this helps mate