The idiom means that it’s time to start all over again. The origin of the idiom is art. The saying is attributed to an American artist named Peter Arno, who published his cartoons in the New Yorker. In a comic strip from 1941, one sees a man in a fancy suit, carrying a bunch of rolled up papers assumed to be mechanical drawings of an aircraft, walking away from a crashed plane. In the bubble above his head, when one reads “Well, back to the drawing board.”