the stack refers to the order of the cards, now the utility of this stack is that the entire deck is stacked in away that it can be cut and re-cut without ruining the stack, neat huh?
Well first there's the order of the Suits. The Order goes Clubs, followed by Hearts, followed by Spades, followed by Diamonds. To help remember that order there's a word that helps, I know it's simple enough that you shouldn't need help to remember the order but some do, the key word here is CHaSeD, see?
ok the suites was(were?) the simple part, now we move on to understanding and ordering the values. To begin with, each card even faces are given a numeric value. The numbered cards are easy to figure out but the faces each have a different value as well. Aces are all 1, while Jacks are 11, Queens are 12, and Kings are 13, easy enough right? now that we have the values figured out the actual order is this: +3
That's right, each following card is a value three more than the one before it. If the card on top of the deck is the 6H(six of hearts) then the next card down is going to be the 9S(nine of spades), and the one after that is going to be the QD(queen of diamonds) but if QD has a value of 12, the next card is three more that would be 15? well because there is no 15 you have to start the count over at 1, so because 15 is 2 more than 13 your next card value is 2 which makes it the 2C( two of clubs)
see how easy that was? maybe? I hope I explained that clear enough
super simplified: CHSD+3
Some notes about this stack before we move on to a routine. If you haven't noticed already three cards separate matching suites thirteen cards separate matching values. Also this wonderful man made a great video explanation
you should check it out if the above was too confusing.