Looking for a template for cutting out the underneath side of a trunk lid of a duster for a wing mounting support

Thank you guys! That would be awesome. It would help me out a lot. I was told that there's some plastic template you can buy but I don't know how well that works or work just for one time use lol. Is there a installation instruction available. My duster has the wing on the back but the underneath side of the trunk was not cut out. So I have the bracket and I am waiting on the proper nuts or the studs