Installing exmoor front seats

I purchased new exmoor deluxe front seats for my 1970 IIA 109. I can feel four holes in the back rest when I press on the vinyl (see lines drawn on the photo for the holes). The seat bracket it should attach to has two holes, one larger on the bottom and one smaller on top (see the circle). I think I'm just supposed to punch a hold in the material in insert the machine bolt. Does anyone have any experience with it? The seats did not come with instructions. I'm also not sure if there is a female threaded bold receiver build into the the holes. I've seen photos where only the bottom bolt has been inserted, perhaps to create a seat that folds down. Attachment 13466