I'm not sure I understand the question. What do you mean by "how do you remember what you just did"?
The premixes on the Cathe DVD's are different mixes of the workouts. For instance, on the Step, Jump and Pump and Step Blast DVD, there are tons of premixes, some which include parts of only one of the workouts, and some which take different parts of both and mix them together. For instance, there's a Step and Hi/Lo Cardio Circuit premix that includes all four sections of hi/lo from SJP and all three step sections from SB, and alternates between them.
Does that makes sense?