How do I add floor/ceiling to an existing plan given to me?

[Max3732]

I got some plans for my house and it has the basic plans as far as walls, windows, doors, etc, but it's missing floors and ceilings. This obviously makes things rather disorienting. It is a 3 story home so the ceilings might be tricky, but is there a simple way to add a floor to the level?

 

What he sent me only shows 1 level, but that's all I need right now since I'm trying to redesign the foyer. I obviously tried the "insert ceiling" and "insert floor" tool and that didn't work.

 

It also has everything as one level and doesn't show the small staircase between the foyer and the rest of the house, but I can work on that later.