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.
Install the storage tray guides into the track (1) on the seat.
Push the storage tray (3) rearward, overcoming the locking tab.