We recommend that you read the first chapter to make sure that you are up to speed with the basic concepts of React and webpack in general. After that, you can pretty much read any chapter you like. Each chapter is standalone, but the chapters are ordered by complexity and may require techniques explained in earlier chapters; the further you are into the book, the more complex the application is.
The application is adapted for real-world use, but some parts are left out, such as proper error handling, and other features that a real-world application would have, including analytics, since they are out of the scope of the book. This book aims to teach you the techniques behind everything. You should, get a good grasp of the building blocks of how to create a web application using React and GraphQL.
It does help if you have been a JavaScript and maybe a React developer for a while, or at least have experience with any other modern JavaScript framework, since many of the concepts are not application-specific but are good practices in general, such as reactive rendering.
But, most of all, it's a book you can use to kick-start your React and GraphQL development learning curve by focusing on the chapters that interest you the most.