You can keep up with progress here, on my website, on Facebook or Instagram.
The main building is a set of three side-by-side brownstone apartments. Like many of the old brownstones found in New York, the structures were typically private multi-level homes that have decades later been converted into apartments. In this prototype, the three side-by-sides, with their four levels, make for a combination of twelve possible units, and it is safe to assume that at least a couple of the basement apartments are reserved for storage, laundry, boilers, etc.
The first thing to do is build a the structural outline. Since this is a 1/24 scale project, I used wood to construct the various apartment shapes with mostly "living room" quarters shown from the front windows (overlooking the street), with shapes or views of spaces beyond towards the back alley depending on the units, and all with about 9-foot equivalent ceilings.
You can see the first apartment details going in in the lower center. That will be Apt. 21B. Like all the open apartments, it will play a crucial role in the story.