not sure of step by step but easy to get out.. but this is how i got mine out.
you have to remove the sunvisors, the rearview mirror, the handles above the doors, and the plastic trim pieces on the A B and C pillars. Then unscrew the dome light and let it hang down and remove the 4 plastic push pin things (not sure what you actually call them) in the back. any it will pop out.
be careful when pulling out since dome light is hanging but once your get it undone form roof you can fit the dome light through the center hole in the headliner and pull the headliner out.
hope that helps..
if i forgot anything someone please post. or if ou know of a different way..