How to divide the big and small sides of geomantic omen

Are you asking about the big hands and small hands of the yin house or the yang house? It's also called getting started, anyway.

Very simple, it is divided as follows: people stand in the central area of a building, facing forward (back to the seat in Feng Shui theory), with the big side on the left hand side and the small side on the right hand side. For example, a house faces south, with a large face on the left (east) and a small face on the right (west). (see sketch)