alrighty,
the 1st pic in the 3rd post shows the wing rib sitting right beside the inside edge of the wing itself. the curved side (thats facting towards the wing), is the side that you'll put some glue on. apply some glue to that curved side, and place it down on the line thats on the wing. if you havent drawn the line, you dont really need to, the line is just there to give you a straight edge so the wing rib isnt put on crooked. if you look closely at the 4th picture, you'll see where the wing rib will sit when you glue it to the wing.
once you've glued the wing rib down onto the wing, you'll slowly bend the trailing edge of the wing down onto the wing rib, and it will follow the wing ribs curve. hold the wing down onto the wing rib untill the glue holds it, then, slowly bend the leading edge of the wing down onto the wing rib, and it'll follow the curve of the wing rib, and once the glue is holding that, you'll see inside edge of the wing itself follows the same curve as the wing rib.
i dont know if i wrote that clear enough, so i drew up a little picture. i hope it helps clear things up. if not, keep asking! if all else fails, experiment with it a bit till it looks like the pictures. simple things can seem complicated at first, but once you figure it out, it all makes sense
nick