grill mounting help

[bsa1969]

hello, I just ordered a new aftermarket inner grill for my 70 c10. I tried calling the tech help line of the company I puchased it from and he didnt know what he was talking about. The inner grill came with new mounting hardware but I cant figure out how it goes on. The holes in the inner plastic grill are square. The nuts that hold it on are square also. Do the plastic nuts go through the inner grill holes and then press into the aluminum outer grill? If thats the way it goes i guess the screws would expand the backs of the nuts holding them in place. Has anyone installed one of these. Any help would be usefull. Thanks