I think I can help with the scale thing. Basically, scale is a ratio of what the model is compared to the real object being represented. So, 1/35 means that every 1 inch on your model represents 35 inches on the real thing. For a figure, a soldier being say 5' 9" tall, or more accurately 69" in real life, would measure 1.97 inches in 1/35 scale.
As far as buildings go, all you have to do is find the dimensions of the building, convert everything to inches, and divide by 35 to get the scale measurement, which you then could draw out and use to make your building. so a room that is 10 feet by 12 feet (or 120" X 144") would measure out to 3.42" X 4.11" on your model building.
Where this all falls down for me is the decimals combined with Imperial measurements. I mean, just how big is 0.97 inches anyway?!! I suppose you could convert everything to metric, and that way the decimals would be easier to measure, but do you really want to do that much math? Perhaps someone else out here knows of some specialized drafting or engineering rulers that make this easier. I hope this helps. Good luck.