Mine were missing on my 2020 Mojave. I went to the hardware store and bought some lock nuts and washers. My wife's hand would fit between the bed and cab. It was a real pain but, we got it done.
It's basically insalled like the instructions say. I went to the hardware store and bought locknuts and washers that fit the bolts. The locknuts and washers went where
jeep was supposed to weld the nuts. Trying to get the washers and nuts between the cab and bed is what took so long. Then...