Absolute pain in the hole to remove. Try peeling the glued edges around the boot lid edge for a laugh.
Once you've lost the feeling in your fingertips with the edges it's onto the main event. The standard metal roof version is held in place with metal rods which need unclipping. If you have a sunroof the headlining is a rigid one piece from memory so a bit more of a handling.
Just make sure you use a vinyl-specific coating otherwise it'll just sit on top of the material and look crap/flake. I would be testing whatever finish you chose on one of the sunvisors before touching the headcloth.