The roof panel (aka "headliner") is held in place by the following:
1- Sun Visor pivot arms
2- Sun Visor support posts
3- Overhead console
4- A-Pillar covers
5- B-Pillar covers
6- Sunroof plastic trim piece
7- Rear dome lights/grab handles
8- C-Pillar covers
Basically once you remove these items -- and the pieces necessary to remove them, (i.e. seatbelt bolts, rear side panels, etc.) the headliner will start to drop onto the seats and dash. Finally, it is held in place above the rear seats with 2 squares of velcro.
In order to remove the seatbelts you will need a T-50 torx bit. There are 2-10mm bolts on the rear panels (1 each side). The sunvisors & rear lights require a T10 or T15 bit.
I hope this helps.