The FusionAuth React SDK simplifies the implementation of authentication flows such as login, logout, and registration in React applications, demonstrated through the FusionDesk example app. Built with React and Node.js, FusionDesk serves as a help desk application allowing users to create and view tickets. The guide details the installation and setup of the FusionAuth React SDK, including prerequisites like Node.js and Git, and provides instructions on configuring and running the FusionDesk application using Docker or manual setup. It highlights the importance of domain matching for successful token validation and the use of FusionAuth's OAuth 2.0 endpoints to streamline authentication without a separate backend. The SDK offers pre-built components and hooks for user authentication and role-based access, enhancing security with middleware to validate tokens. The application showcases various components, including login, ticket management, and profile pages, illustrating practical use of FusionAuth for user management and ticket operations, ultimately promoting secure and efficient user authentication processes in React applications.