The beginning stages of the Eternal Beach-Body Workout Plan are all about creating a foundation for later muscular development. And while "foundation" typically refers to baseline strength or musculature, this workout plan is also dedicated to enhancing your mobility, particularly in sensitive joints like your shoulders and hips.
Without fluid hips and shoulders, foundation-building exercises like the bench press and lat pulldown are all but impossible—so focusing on these mobility exercises will be especially important in the long run.
Do each exercise as straight sets; complete all sets of each exercise before moving on to the next.
Make sure you pay attention to the designated rest—45 seconds isn't a lot of time, and you'll be well served by tracking your rest periods on your watch or your phone.
When doing mobility exercises, make sure you use light weights, if you use weights at all. You'll be training small stabilizing muscles, so you don't need much weight to benefit.