The grille assembly installs from the backside so the front fascia will need to be removed. There are two 10mm bolts at each end of the fascia and 6 scrivets (GM's fancy word for a reusable plastic rivet) that need to be removed from the engine compartment area. The scrivets can be detached with a panel/clip removal tool like the one shown in the photo. You'll want to use the tool to pop out the center of the scrivets, which will release their hold so you can pull the entire scrivet out. There are also two more 10mm bolts under the car that need to be removed.