Our apartment is the first floor of a house, with another unit composed of five bedrooms occupying the second and third floors. Also, I realize my labeling of the neighbors' front door and hall are confusing - we only have upstairs neighbors, and their front door is next to ours and opens into a little front hall for them, then there are stairs that lead up to the rest of their unit (which we've never seen). So their "downstairs front hall" is on the same level as our unit, it's just "downstairs" as compared to the rest of their apartment.
Note: I did my best, but this is most definitely not to scale. Also, the spaces with question marks are probably just normal parts of the house's infrastructure (ie where wires, plumbing, heating vents, etc are), but I just wanted some way to indicate that they weren't spaces we have access to.