Each program is set up circuit-style, meaning that you will go through usually 3 movements one after another with little to no rest in between. After you complete one set (the 3 back-to-back movements), you will then take a short rest of 30 seconds-1 minute before repeating those three movements for the second set. Repeat this process until you complete all sets for the first circuit
(your program will tell you if it's 3 or 4 sets).
After you complete all sets in the first circuit, you will move on to the second circuit and do the same thing until you complete the workouts.
NOTE: If you are training with heavy weights, you will likely need to take longer rests in between sets.