How to Use This Book

This isn't a book you read on the bus and leave on your nightstand. It's a manual. Every chapter ends with something to do, and what you do in one chapter is the raw material for the next. If you skip the homework in chapter 2, chapter 5 won't do you much good.

You don't need much:

• Blank paper. Letter or A4 is fine. If you can get A3 (or 11×17), even better, because the flow diagram needs room.
• A pencil and an eraser.
• A thick black marker. The kind that won't let you draw details. That's on purpose.
• Two highlighters in different colors.
• Post-its, if you have them.
• A folder on your computer named after your app. The one for our example is called falta-uno.
• Access to some AI that writes code. I'll tell you which ones later, but you won't need it until Part Three.

The rhythm

Read a chapter, do the homework, let a day go by. Seriously. App ideas have a strange property: at night they look brilliant and the next morning they're full of holes. Those holes are information. If you find them now, on paper, they cost you nothing. If the AI finds them, they cost you an afternoon of back and forth. If a user finds them, they cost you the user.

The boxes

Throughout the book you'll see three kinds of box.

A line worth highlighting. These are the ideas I want you to walk away with even if you forget everything else.

The folder

Starting with the first chapter, you'll be filling up a folder. By the end of the book it'll look roughly like this:

falta-uno/
├── README.md           the app in one sentence and an index of everything
├── idea.md             what it does, how it makes money, what it needs
├── landscape.md        who we're up against
├── brief.md            who it's for
├── story.md            the app, told in words
├── flow.md             the flow diagram, as text
├── screens.md          the list of screens
├── data.md             what the app has to remember
├── design.md           color, type, tone of voice
├── sketches/           photos of your paper drawings
└── AGENTS.md           the rules for the AI that's going to build it

Don't build it now. It builds itself, chapter by chapter. I'm showing it to you so you know where we're headed.

One rule before we start

Everything you write in that folder, write it the way you'd explain it to a friend who knows nothing about your idea. No jargon, no selling, no "revolutionary" or "disruptive." The AI is that friend. It takes everything literally, and it can't ask you what you meant while it's writing code at three in the morning.