WARNING: This page is about a different car, the 2003 Pontiac Sunfire and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Position the grille (2) to the I/P trim pad (1).
Install the grille (2) to the I/P trim pad (1), pressing into place until fully engaged.
Fig 1: Installing Grille To I/P Upper Trim Pad (Pontiac)