Elma, in every video of Sam, he draws the Supply/demand level manually. You can check post # 357.
The basic basic concept is, if anything rose(or fell) dramatically from a certain level, he marks the level as huge demand (or supply) level and marks it as key level he would be interested in for reversal watch.
The more the level is tested, the more the level moves from disequilibrium towards equilibrium. So, he wont be interested anymore in that level and would look for such fresh levels