Simple straightforward despite initial sceptism of the room shape and it’s collums. Transfiguration is the practise of transforming animals into objects and back and also governs the practise of animagi (transforming ones self into an animal). The classroom (1B) is on the ground floor and attached to a courtyard where Malfoy gets transfigured into a ferret and (spoilers) where Dumbledores body is found.

More to come obviously but considering my classrooms are the same size or bigger than a lot of sets you can imagine how big the finished product will be.