This demo is on a JM-1065 with the ceiling wiring already done.
see "Dollhouse Wiring" for more on using tapewire.
In a JM-1065, the dividers line up with the Gable Side in front.
Line up the top of the divider with the edge of the stair hole.
The divider that is laying on the floor is lined up with the back edge as a "square" to make the divider straight front-to-back.
Mark the floor for the divider's position. Mark the Front so you have a target when the time comes to install the divider (in the 1065, the Gable Side is the target in front).
Move the second divider upright so the divider is straight up-and-down. Check again that the divider lines up with the stair hole. Mark the floor for the divider's position.
Do the same thing for the second floor divider... check the front edge if it must line up with a gable wall (this takes priority over lining up the stair hole). The back edge must line up with the marks for the first floor divider so that, when the dividers are installed, they will line up with each other.
Tip the divider and put it in the house about 1/2" from touching the front wall. Touch the bottom edge down lined up with the marks in back and in front.
Stabilize the divider as you tip it upright. Take care to keep the base of the divider lined up with the marks (I push down with the hand holding the divider so it won't wobble around and smear the glue).
When the divider gets close to the floor above, lift the floor as much as you can.
Line up the top and bottom with the marks. Make sure the front is on-target; check the mark, check the stairhole cutout
Keep the front of the divider lined up with the target; push the divider the last bit into position
If the "target" is the Gable Side, tape the divider to the Gable Side so it will stay lined up - stretch the tape to keep it tight.
A damp rag cleans up the glue squeezings
Mop up the dampness with a dry rag
Repeat the process for any more first-floor dividers, then do the second-floor dividers. Work from the bottom of the house to the top. Tape the dividers to keep them in position as the glue dries.