WARNING: This page is about a different car, the 2007 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
Position the front fender liner to the fender.
Fig 1: Identifying Push-In Retainers In Front Fender Liner
Courtesy of GENERAL MOTORS CORP.
Install the front fender liner with the push-in retainers.