A JavaFX application with Couchbase Mobile can be used to create desktop applications with rich user interfaces and fast data access. To get started, one needs to clone the TodoLite JavaFX source code, set up the project in IntelliJ IDEA, and add the Couchbase Lite library as a dependency. The application can then be used to create and persist documents, and sync them with a Sync Gateway instance. The Sync Gateway configuration file defines settings such as database names, users, and security rules. By adding replication to the JavaFX application, it is possible to synchronize data between multiple devices or applications. The next steps include learning about the Sync Function to define access rules and Couchbase Lite Views to write custom queries.