In an interval training workout, you'll do short intervals of hard exercise alternated with short intervals of easy exercise. And yes, even beginners can do interval training.

Here are the guidelines for judging your intensity.

Level 1/10 - Standing still at rest
Level 3/10 - Recovery level - ie. walking at a slow pace
Level 6/10 - Regular long, slow cardio pace
Level 7/10 - Beginner interval intensity
Level 8/10 - Intermediate interval intensity
Level 9/10 - Advanced interval intensity
Level 10/10 - Running for your life! (no need to do intervals at this pace, ever!)

"No matter what your fitness level, you must drop down to a 3/10 intensity level between workout intervals."

Here’s what that means. In most of the 4 minute miracle workouts, you are going to do 20 seconds of work followed by 10 seconds of rest. While the 10 seconds of rest is super short, it’s important to let your body come back down a bit from the high intensity it just went through. If you didn’t take that critical rest periods, you’d basically be doing steady state cardio, which we know from research is not the most effective way to lose weight. Therefore, that 3/10 intensity level between intervals is your resting level. In other words, if you just did 20 seconds of burpees (at an intensity level of 9/10, then your short rest period would come down to 3/10, which is basically your resting heart rate level. I hope that makes sense and answers your question.