Hi

So my client does not have existing drawings of their building, so I'm building one from scratch within Stardraw.
I need to take this drawing I make and plug it into another program for modeling.  Scale is important, but +/- a few inches is ok
I know some dimensions.  I know from wall X to wall Z, the distance is Yft.
How do I set the scale of my drawing?

I watched the video
FAQ - Fixing the Scale of Imported PDF Drawings

This seems to be for setting the scale to an existing, imported drawing. 
I feel like I need to do the opposite of what the video recommends.
I'm having a hard time wrapping my head around it.  

Thanks!!!