The plane is set up so that the wing may be broken down into 2 pieces for easy transportation and storage. To use, just slide each half onto the wing tube and fasten to the fuse as you would normally fasten a 1 piece wing.

As far as the directions, maybe they haven't been updated. Not too big a deal. This is a pretty straight forward assembly. If for whatever reason you'd prefer a one piece wing, use the wing tube in place of the dihedral brace. Slide everything together, line it up, and glue away....