When you enter the house to the front door you see the little stairs in the end. That also is the border between the front house and the back house. Behind the doors in the back is the main reception room. The doors in front on the left are there just for the effect. They have no function otherwise.
Looking through the door you see the living room from the family who lives here . This style is Louis XVI (1782).
Standing on the little marble stairs from the first picture looking in the courtyard you are seeing this wall decoration original from 1728. The 2 doors are secret toilets from that period. A brick layered sewer gave direct access to the "Herengracht" canal in front and until the sixties of the 20th century the canal houses watered directly on the canals in front with their sewage.
In the garden you have a nice view of the garden house that nearly every canal house has for placing apart their piece of ground from the land on the other side and to impress visitors. Also a lot of house owners were rich jews who used their garden house for the feast of Tabernacles ( Sukkot ).