Tell them you need a main enterance to access a building: Wide doors, fire safety regs. Next you need wide hallways, leading to atriums, with smaller doors, le

Tell them you need a main enterance to access a building: Wide doors, fire safety regs. Next you need wide hallways, leading to atriums, with smaller doors, leading to apartments, individual rooms, cupboards, shelving, etc. A building is hierarchical, and similar to a file system. You can explain flow of people, flow of stuff, storage, whatever.