Attach the left and right fuselage shell together. Take care they are correctly aligned all around. If necessary, sand the contact area flush to create a neat joint. Once satisfied, apply a bead of thick cyano or MS polymer glue on the right fuselage shell. (Slow-setting glue is required here to give you some time to align the fuselage shells correctly - and double-check it). Attach the shells together, check the correct alignment and secure them with modelling pins or masking tape until the glue sets down. Double-check that the fuselage is straight and untwisted; looking along the longitudinal axis of the fuselage, the joint of the fuselage shells must be straight. Take extra care of the good alignment at the wing and tailplane area. This is the most critical step of the entire assembly - now you can make a straight and true fuselage that will give you a pleasant plane to fly - or not.
