Here are some great HIIT sessions we have found that you could use

HIIT Fit Friday Challenge 20th March:

https://www.youtube.com/watch?v=ml6cT4AZdqI

* 20 Minute Hiit Workout with Olympic diver Leon Taylor

https://www.youtube.com/watch?v=sqB2xf3Sn4o

* Simple HIIT workout for any age

https://www.youtube.com/watch?v=kAXg3cM0UCw