The total floor area of the house is 120 square metres. These plans show the layout. Although the rooms are roughly to scale the furniture marked in them is not!
The plans are not intended to be accurate and exact but do give a good idea of the layout of the rooms and the main items of furniture in them.
And yes - the wall down the middle of the house really is a three quarters of a metre thick and there is no passage through upstairs!
The beds in bedroom 3 are bunks