Most roof top tent units need to have a pair of mounting tracks attached to the bottom before you can use them.
Having done this more than a few times, here are a couple of tips. Start by taping the nut in place over the holes in the mounting tracks
Then drop an ice pick through the first attaching hole to aid in aligning it with the hole in the mounting track. It normally takes some wiggling around to get the nut aligned up so the bolt can be started
This especially helps with the track farthest from the door, it’s hard to lower and look under the platform to align things. The mount tracks attached and ready to go.