Well, it is not very clear - even at Wannsee, there is no single piece of paper that says, our five year target is to eliminate all Jews, or somthing similar.
You have to read between the lines of their planning instructions and railway building plans. Albert Speer plays a much bigger role in this, and his real role is only now really becoming obvious.

But how soon it was know in German municipal bureaucracies that there was violent solution to the "Question about the Jews" I know from a story in my family. Apparently my Grandmother, who was working as office manager for the major in her hometown, was able to warn jewish families in the town of the impending deportation, and this story, which I have never been able to verify with my gran, must have happened before 1936, since she stopped working there, when she had my mother.