After having cut out all of the fuselage. Begin folding it along the dotted lines. Then tape your fuselage together at the front, back, and across the fuselage at the fin. After you've folded all the lines correctly, you should now cut along the line in the middle of the fuselage. Do this by folding the fuselage to the right, making a cut, and repeating the fold to the left. Then fold as indicated the second line near the rear of the airplane by folding the 2 rearmost boxes forward and cut along the line.