Paying attention to your form is definitely important when you’re doing bodyweight workouts, but the risk of injury goes up when you add more weight. Be sure you’re stretching regularly, and whenever you have the opportunity, work with a trainer, physical therapist, chiropractor or structural integrationist who can help keep your bones and muscles working together and lined up.
Complete the exercises in each workout as Straight Sets. For example, you'll do one set of leg presses, rest for 30 seconds, do a second set, rest, do the third set. Then, move on to the next exercise. You'll complete all movements in both workouts this way. Complete 12 reps of all movements for 3 sets each, and rest for 30 seconds in between each set. Choose a weight load where the last two reps of every set are extra hard, where you wouldn't be able to do a 13th rep. You may find that you increase the weight load for each set while keeping the 12 reps for all three sets.