In the video, a man is standing in front of a whiteboard with a diagram drawn on it. He is wearing a light blue shirt, black pants, and a black tie. The diagram on the whiteboard is a model of stairs, with arrows pointing to different parts of the stairs. The man is pointing to different parts of the diagram and talking about it. The background is a classroom with students sitting at desks. The video is shot from the perspective of someone sitting in the classroom.