This is clipped from the construction description "Enkla Stugan". The horizontal liggreglar (49) are beveled in the inner corners so it's possible to nail the standing hörnreglar (25).
Can't you just simply move the hörnreglar 45 mm "outwards" from the corners (or at least one of them) to avoid that process? Or do they need to be placed so that the corner is held together by hörnbeslag (26)?
"Hörnregel som monteras efter beslag" seems to have been omitted in the accompanying construction video. Since I will have boards and not paper externally, I probably need it to nail into. Träguiden has a slightly more complex solution, where one hörnreglel has been moved so it becomes easier to fit in the horizontal reglar. But then added another regel to bind it together well(?)
Stuff to ponder.