I would look at a few of the others that are similar, the new instructions have mostly a combination of the same steps applied to the various kits. This one has the separate windows, that step is in the newer instructions, the roof top water tower is documented in the stand alone roof top water tank.
these particular modes have 5 walls four on the outside and one in the middle for the second floor fourth wall. Use a square to alight the walls and block the inside using the wood provided for support.