Sometimes I do group fitness at my gym and the classes are HIIT based. Sometimes when I don't feel like leaving the house I look up HIIT training on pop sugar
YouTube. They are all free and have TONS of workouts! Try doing weights for your "low" or "off" drill and doing something low impact like lunges or squats for your "high" drill, just do them faster. Hope that made sense lol! Hope you find a good program! Is turbo fire a Shawn T program?