How would I save a players custom built apartment?

So in my game players will be able to buy and place furniture in their two-story apartment, but I have no clue how I would save how much of which furniture he had, where it was, and how it was oriented or how to use data stores to save that. I know it is possible because ro-citizens does the same thing except with a one story apartment. I already know how to save basic things like money and exp, but not a custom-apartment.