I put this is the same 1/2 gallon ball jars we keep our raw milk in, cover, shake it up good and set it on the counter 12-24 hours – depends on room temps, etc. You can tell by the sour smell when it's ready – it's not an unpleasant sour smell though.  NT says it is done when the milk thickens and it curdles slightly. Store it in the refrigerator. THAT'S IT!