This is one of our favorite, go-to interval workouts when we aren't near a track and need to add some variety to our runs.
The speed/fast portion should be done at 80% max which is a very fast effort but not a sprint. You should be able to recover and jog SLOWLY after each fast repeat. If you have to walk or have a pukey feeling after one of the repeats, you ran too fast.
If you are new to speed/interval workouts, do 2 sets of the pyramid with a 2 min break between sets. Build up to 3 sets.
Enjoy and happy (fast) running!