Step 0 is all about identifying a problem that someone is having. As we move on from Step 0, we need to figure out what we want to learn about our users and their problem. Then we build in small increments so we can validate that learning.
You have an idea. How do you become confident in order to build the right thing to solve the right problem without wasting your money? We believe that the best way to do this is to build in small increments, get feedback from humans, learn from it, and adjust based on what we learned.