Ayrodynamics of Sailing
That is one question that really cannot be answered on a bulletin board. You are really asking how do you adjust sails and that unfortunately is a question that would take a book to provide the technical answer. If that is what you are seeking I suggest that you try to find a copy of C.A. Marchaj''s ''Sailing Theory and Principle''. Other good sources are Bethewaites ''Performance Sailing''. If you are only looking for the answer in a simple enough form that you can get out on the water, then my current favorite ''learn to sail book'' is Steve Colgate''s wife''s book called something like ''Sailing for Women''.