Your dealer ripped you off, should've came with a bag with 14 square nuts, 14 screws, 2 retaining washers and 4 plastic nuts. Cost $150 straight from GM delivered to your dealer.
You can download the instructions with all the contents listed if you just go to chevy.com and look up the liners under owners section and go to accessories. The instructions are bad but they do get you the general idea.
ISheets_84263803.pdf