Hello Mike ,
I dīont live in a old castel , but in a little house with the best wife
and thatīs the way because I can keep all models in the rooms
now lets go on ...
Glue part U 21 on both sides with parts U23 after the frames U21A + B have been inserted ... Install U 22 on the inside where the connection U 22B will later be glued in
Connect the two parts... and attach the rudder
Sincerely
Kurt