Being primarily a ship modeler, I set this project aside for a while. Part of the problem was that I’d discovered that I was missing one small set 4 parts, all the same. There are a lot of parts in this kit and they are well packaged and labeled, but it took a while to go through and check and re-check and then to figure out exactly how the part was shaped and how it fit on the model.
The pieces are parts of the lower roof and cover the corner joints. Outwardly, they just look like simple wood strips, but they need to be groved on the underside in order to sit down on those corner joints. Also, they need to be thicker than the other roof boards to allow for the groove.