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.
Remove the 7 retainers that secure the panel to the retainer.
Remove the rocker panel molding.
Fig 1: Removing 7 Retainers Securing Panel To Retainer