WARNING: This page is about a different car, the 2004 Buick Regal and 2004 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Front Door Opening Carpet Retainer Clips
Courtesy of GENERAL MOTORS CORP.
Install the carpet retainer to the vehicle.
Position the door carpet retainer clips to the carpet slots and push down to secure.