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.
Remove the front door sill plate. Refer to Door Sill Plate Replacement - Front in Interior Trim.
Fig 1: Pinch-Weld Flange Weatherstrip (Front Door Opening)
Courtesy of GENERAL MOTORS CORP.
Remove the weatherstrip from the pinch-weld flange.