All the house labelled spaces on the left are just different parts of the one house.
Basically the first picture shows the house split up by a series of large doorways, the walls either side of which encase hidden corridoors.
The second picture shows a large fireplace that is accessible through the camera runs which encases a hidden room.
Both could be unveiled to the housemates later on, used as part of tasks or accessed by the presenters or crew to enter the house when the housemates are in other rooms without them being any the wiser. Passing right amoung them
.