First, you should plan to follow the instructions in the writeups. Here's the links to all parts for quick reference: Part 1 - Server Setup
(After part one, the series splits into 2 branches - one that uses Redux for state management and another that uses React's native Context API instead.)
Using React Context Part 2 - React Setup - React + Context Part 3 - Security and UX - React + Context
Using Redux Part 2 - React Setup - React + Redux Part 3 - Security and UX - React + Redux
The purpose of these tutorial series is to give you a taste of what it means to include token authentication in a project. It doesn't aim to teach basic principles of Node/Express, React, Redux, etc.
The writeups listed above assume a basic understanding of JavaScript (ES6), promises, React, Node/Express, and either Redux or React Context, along with some other more advanced principles of React like Higher-Order Components.
This is an open-source project and may very likely have mistakes in it. All PRs are welcome.