Open the drawing-model pair of the foundations and select a
floor structure
Open the drawing-model pair by double-clicking
Foundation in the project's document browser.
Select
Floors and Ceilings > Add Area (Floor, Ceiling,
...).
Select Floor from the list.
Do either of the following:
If you have not used the adding function before, the list for
selecting a structure opens automatically.
If you already have used the adding function, the previously
selected structure is the default. Change the structure by first
selecting the Select Material from List function
from the contextual toolbar. The function opens the list for
selecting a structure.
Select a floor structure from the list, for example
FLR-SLAB80-STY.