Upstairs and 2nd door on left.
later - forgot to say that in the flat below me it would be through the front entrance, along the corridor, down the stairs, first door on the right. The layout of this house is weird, the lower flat (technically it's called a "maisonette") is technically on the ground floor and basement, though the entrance to the ground floor is about 8ft up a flight of steps. My bit is technically the first floor (US second floor) and attic, but the entrance is also on the ground floor.