2-5mins of either jumping jacks (star jumps) or skipping (jump-rope)
Workout - 20mins
As many rounds as possible (AMRAP)
One round =
15 Air Squats
15 Push-ups
15 Situps
Set a timer for 20 minutes
Count rounds completed plus the number of reps completed on the last round - record your total here

Please take a look at the technique in the videos below:
Squat demonstration
Pushup demonstration
Sit-up demonstration
If you have not been stretching after workouts, please ensure that your hip flexors, shoulders, glutes, and triceps and well stretched every day.