This model was essentially copied off of a standard hanging bracket from my own mini blinds that I own. The larger holes are there to allow a drill or screwdriver to reach the smaller holes for hanging. The holes on all sides are so that you can attached the bracket to any side of the inside of your window (or the outside).

If you want to buy this remade, visit empirehomefashion.us and you can find it there!

I found printing with PETG is much smoother for getting the cover into the bracket. PLA is plenty strong enough for hanging purposes though. 

I would suggest printing them separately as printing the two together caused some problems in the print for me.