To route the wires better we used little straws (actually plastic coffee stirrers); the wires are very thin so it was easy to fit up to 4 wires inside the tubes). One of the hardest parts is the wire routing as you have to build the model by sections and before placing the furniture. It gets hard when most of the walls are in place unless you have a lot of experience building miniatures.
It took us (wife, daughter and myself) several hours in the span of a couple of weeks to finish the model. Everything in the box picture is inside in the form of pieces, raw parts and blueprints for fabric cuts. The manual is sufficient guide to complete the project, but the scope of the work required may look overwhelming. If you plan ahead and review the photos on the manual and box you can implement some modifications that may suit your preferences better. We decided to enhance the realism of the bathroom adding a toilet and a lavatory and changing the layout to accommodate these items (see photos). I designed and 3d-printed these (if you want the STL file I can provide it so let me know) and painted some parts to go with the theme.
On the bedroom the table lamp was designed to be illuminated from behind by one of the LED's. We decided to build the lamp with the LED inside because it would look better from any angle. It was an easy modification that paid off. There was a convergence of wires to tie on a roof corner after the top roof was glued in so we placed a circular mirror covering there while providing visibility of the stairs from the bedroom to add a little bit of realism.
As others indicated this is a kit that requires not only assembly but actual manufacturing of parts. There is a niche community of miniature builders that work on similar projects starting from actual scratch so this kit makes things much easier with all solid pieces well cut (requiring only glue to put a piece of furniture together).