It is a great idea to warm up before starting the plan. I recommend a 10 minute brisk walk or rehearsing the movements and gradually increasing load (as you noted).
To progress I recommend the “2 for 2” rule: At the end of your last set if you can perform two extra reps with good form – for two workouts in a row – increase the resistance 2.5% – 5% the next session.
You can add bands to the bridge and resistance to the calf raises and any of the other exercises. I would advise staying in the 60% of 1RM target for weight, a touch higher if you consider yourself an advanced lifter.