The gym program already has recommended cardio inside the actual program but the home version does not. Cardio is OPTIONAL and not required to see results. Due to my workouts being pretty high intensity, you will already be burning a good amount of calories and fat. As a general baseline, I recommend my app clients add in cardio 2-3x a week around 20 minute sessions (if you are in gym program, this is already laid out for you.)
Remember you do not want to overdo the cardio because it can be detrimental to gaining muscle and can slow recovery time between workouts.