square meters of an appartement

[nkat]

Hello!
I found this incredible software and get started right away hoping to figure everything out while drawing
Created this plan (attached), now I'd like to create a sheet estimating how much building materials would go. For that I'd like to have square meters for each surface (floor, walls).
Would someone please tell how to achieve that?

[Mike53]

go to file > preferences to cselect your preferred unit of measurement