Based on my videos:
https://youtu.be/jmD64iT2Aes
https://youtu.be/bFbx2pQX120
This is a high intensity cycling plan but is applicable to running and triathlon as well. This is the more beginner version of my quick high intensity plans so you do not need to have a large base level of fitness but you should be riding at least 2 or 3 times a week before attempting this plan.
Some notes on the high intensity intervals
Keep Cadence above 85 at all times during the high intensity intervals, your cadence can be lower during recovery
Whether you nail the workout exactly or fade is not really important, you'll get the max benefit of this workout as long as you're putting in top end effort (even if your legs begins to fail)
10 years experience as a one-on-one endurance coach including working with hundreds of athletes both local and abroad while simultaneously being the Head Coach of the University of California Santa Barbara (UCSB) Triathlon Team. I've coached beginners through their first event all the way up to professional Ironman athletes.