Warm-up sets are a great opportunity to focus on the movement before you give 110% in the working phase of the exercise.
Neil’s point about stopping short at the bottom of the movement (with the dumbbells 3-5 cm above your chest) is a good tip if you want to keep the load off your shoulders and zone in on your chest. And, as Flex does in the clip, if you want to develop the upper chest you can achieve this by performing the exercise on an inclined bench.
Chest flyes (6m06s in the clip) are an opportunity to work the pectorals from a different angle, and Neil’s teaching points about keeping your knuckles parallel and not going too deep, are sound advice.
Also, I like their addition of machine chest presses (9m24s in the clip) to close out the sequence. Your chest will be fatigued from the dumbbell moves, but there’ll still be some fuel left somewhere in the tank and a machine will make it a bit easier on your body, while still extracting the best of what’s left in your pecs.
Have fun with it : )