Architectural Questions

I am having trouble using this program for architecture thus far and tutorials for such are almost non-existent.  Since I will be drawing in feet and inches and drawing wall sections I am left with two questions.  When creating Richlines what are the units of offset measurement?  It seems to only allow feet in my case.  I could draw walls in plans without richline, too, but the command prompt area won't let me type in inches with fractions, like 7 5/8".  Is there a way to do that?