WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
Align the roof auxiliary air outlets to the holes in the headliner.
Press the roof auxiliary air outlets into the headliner, locking in the retainers.
Fig 1: Installing Roof Auxiliary Air Outlets Into Headliner