Complete all the workouts shown for each day. Rest 5 minutes between each video
No please do not force yourself to continue if you are too sore. Rest an additional day and continue where you left off. However if your chest is sore but today's leg day, you can continue with leg day.
It is suppose to be challenging so that you improve! Maintain good form when completing each rep, if you really need to rest just pause the video to take a quick 15 second break and continue
Of course not! The man is simply as a reference as how the exercise should be done. It is highly recommended that you perform the workout at your own pace as all of us have different fitness levels. What matters is you complete the entire workout each day!