In the video, a person is seen assembling a mechanical device. The device consists of a metal plate with a circular hole in the center and two protruding arms. The person places a cylindrical metal piece with a hole in the center onto the plate, aligning it with the hole in the plate. They then attach a black circular piece with multiple holes around the edge to the cylindrical piece. The person proceeds to insert a metal rod into the cylindrical piece, securing it in place. Finally, they attach a black circular piece with a hole in the center to the rod, completing the assembly.