The expanding screws are used to hold the side number plate to the airbox/subframe. One each side. The left airbox cover has a tab that folds around the subframe, and that tab has a slot. There is a hole in the subframe, simply line them up and tap them in. However, they are foolish bits, and I replaced mine with a machine screw as the only way I can easily remove the airfilter is to remove the left side plate, which requires removing that plastic scrivet (screw/rivet, actual part name at Boeing). It will break eventually, FYI.