You must assemble and finish the bedroom closet before you do any other finishes to the bedroom.
Assemble the Second Floor Left Partition and Second Floor Closet Wall before installation into the dollhouse. This will allow you to finish the interior of the closet.
Wallpaper the area of the bedroom where the closet will go and then wallpaper the Second Floor Closet Wall on what will be the interior of the closet.
You only need to wallpaper three walls of the closet. You do not need to wallpaper the wall where the door opening is since it will not be visible from any angle.
The ceiling will also not be visible from any angle so you do not need to finish it in any way.
Once everything is dry, you can install the sub-assembly. You will need to use a mallet to tap it in place, making sure the Second Floor Closet Wall is flush with the hallway wall. Clamp and let dry.
You can see how the closet looks finished in the interior now that the sub-assembly is installed.
Keep In Mind
You certainly do not want to apply ceiling paper to this room yet because it will not allow you to install the Second Floor Left Partition and Second Floor Closet Wall sub-assembly you just built.
Do not apply flooring either until the sub-assembly is installed.
