WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
Align the rear headliner trim finish molding to the retainer in the roof.
Press up on the rear headliner trim finish molding in order to engage the retaining tabs and clips.
Fig 1: Installing Rear Headliner Trim Finish Molding