What are the goals of the program? To increase mobility and range of motion in your muscles! This helps prevent injury and increase performance.
How to get the best outcome of the program? I’d use the stretches and movements for either warmups before a lift, or as something to implement weekly so that you can maintain proper mobility in your muscles to prevent injury and improve performance in the gym.
Who are these workouts for (skill-level)? These are for everyone. Granted, your mobility may not allow you to perform these movements with full range of motion initially, but do what you can (if you feel pain rather than discomfort, do not continue and push through). Your mobility will improve over time as long as you are consistent with the movements.
How to schedule the program into a week? I’d do a lot of the lower body and lower back movements on a leg day as a warmup before you lift. You could also perform these movements any time — but I’d recommend on a rest day as well.
What do I need to participate in this program? Just yourself and the desire to get mobile!