WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Install the right and left side air baffles to the vehicle.
Install the right and left side air baffle push-in retainers.
Fig 1: Installing Right And Left Side Air Baffles & Push-In Retainers