It's the same thing. You start by talking to customers to get an idea of what to build, then you create a mockup of what you'll build and then show that to cust

It's the same thing. You start by talking to customers to get an idea of what to build, then you create a mockup of what you'll build and then show that to customers and iterate until there's demand - now you have your first set of Things to Build, and they'll all be "Enhancements" at this point, since you haven't built anything yet. Once you've done that, you get that first draft in front of customers, collect feedback, and you'll find the feedback is a mix of "x is broken" and "wouldn't y be cool". And you're off to the races.