There ended up being two little holes drilled out under the covering on the main wing panel just in front of where the aluminum tubes end. Naturally, I was a little put off by this since the instructions have no pictures, no text, nothing indicating what to do and there is no hardware for attaching the wing. So, I'm either going to go with jrf's idea for install, along with the blocks already installed in the outer wing, or I'm going to epoxy the whole thing together and call it good. Here's a picture of where the holes are.