Like Tim posted above, you need a free-floating center bow which the edge of the headliner halves slides into and a bow at the back which is attached with 11 small screws. The headliner and both bows should be visible in this photo.
RdsLessTaken/Don

http://s1291.photobucket.com/user/RdLessTaken/media/IMG_8574sm_zpsf606d867.jpg.html