WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Position the scuff plate to the rocker.
Apply downward pressure on the scuff plate in order to seat the retaining tabs.
Fig 1: Removing/Installing Front Rocker Molding Scuff Plate