I need help again. please see my video https://www.youtube.com/watch?v=von73a9liH0 and respond on this forum, please.
Looking good, actually!
The gap: The fuselage does not fit IN the gap, so what you have is correct; it sits on top of the wing. ALSO: Trim back the two spars that are in the gap in the wing - that is where you will slide the battery (slide it in from the nose).
The nose: The two side edges on the nose should have score-marks where you should remove a bit of foam, leaving the paper on the outside - this allows a bit of overlap on the sides for you to glue the nose to the fuselage. If you trimmed it a bit short or long on one side, don't sweat it, just trim and glue to fit using the bottom point as your guide, and make sure the nose is straight to the fuselage.
The bottom plate: That bottom piece goes on the rear-underside of the fuselage, just aft of the wing.
You're close, keep it up!!