Probably the best way to explore HIIT is to browse YouTube and find a workout video to try out. There are many options, of varying lengths, aimed at everyone from beginners to more advanced athletes. HIIT comes in many guises and subcategories, such as Tabata, EMOM (every minute on the minute), AMRAP (as many reps as possible), and more. You might want to experiment with a few different styles until you find one that matches your goals, stamina, and allotted time, and either pick one type to focus on or mix them up. You could even pick a single video you like and exercise to it every time. Don’t spend too much time debating this, just try out a few and see what works.
Fundamentally, all these forms of HIIT follow a similar pattern: a set time performing reps of a particular exercise, followed by a brief rest period, and then by another exercise, and so on. Tabata, for example, comprises twenty seconds of work, then ten seconds of rest, etc. The exercises vary from strength training techniques like squats and crunches, to aerobics like jumping jacks and jogging in place. Regardless of the specific style, the goal of this type of training is to work your body as hard as you can during the exercise intervals, and then rest in between, squeezing a lot of intensity into a brief time period.