The entrance to the bottom floor was on the south side of the temple. A stairway led up to the middle level, and from there to the third floor.
KJV
The door for the middle chamber [was] in the right side of the house: and they went up with winding stairs into the middle [chamber], and out of the middle into the third.
ASV
The door for the middle side-chambers was in the right side of the house: and they went up by winding stairs into the middle story, and out of the middle into the third.