WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
Install the door sill trim plate to the vehicle. Align the retainers along the door sill and press into place.
Fig 1: Installing Lift Gate Door Sill Trim Plate To Vehicle