What Has Been Done
Before actually starting on connecting the flats, I actually went back to my centre piece, the table in the centre, and retouched it to make a better final product, making use of the Bevel Tool to give it some curves and a more finished look.
Next up I finally get started on creating the connection between the two flats, first creating what will be the roof to the lower flat but at the time is a simple block, my reasoning being so the hole in the roof of that flat will match up perfectly with the hole in the floor of the higher flat. Once that is ready I created an object the shape and size I wanted my hole to be and used difference on both to create a clean cut through. I then created a new file with both apartments in it, set out how they will be in the final product and fitted the roof.
I then proceeded to add the ladder my character would use to move between both apartments. Once that was done, I had officially finished working on the building itself and was now ready to start working on the second stage: Detailing.
Camera Shots of the First Stage