Questions for Giana Regarding 3 x 5 minute intervals

Here are my questions about this specific workout:

1. What is the purpose of 5 minute intervals? What energy system am I training? Where should the effort be in relation to LT?

2. How long should my warm-up be? How long is recovey between each effort?

3. What is the preferred terrain? If I can't find a flat stretch to do this without wind, should I do the efforts into a headwind or a tailwind?

4. If I can't maintain target watts, do I modify the workout or abandon the intervals?