To work with XOD, you use the XOD integrated development environment (IDE for short), which comes in two flavors: browser-based and desktop version.
You can start the browser-based XOD IDE simply by visiting the link. However, because the browser has relatively few permissions to access the computer’s file system and USB-ports, its capabilities are quite limited.
Notably, you can’t upload your program directly to the board from within your browser and you won’t get the convenient save/load functionality.
However, you can import/export your programs as a single file (known as a xodball), generate source code that you could copy and paste into an Arduino IDE, and then upload it to the board via the Arduino IDE.
XOD IDE for desktop requires installing, but provides all features. It works on Windows, macOS, and Linux. Find a distribution package for your system on downloads page.
Once you start XOD IDE, you’ll see the welcome-to-xod
project open. It’s a tutorial project split on many small lessons. Follow instuctions in its comments to learn XOD. There is a web version of the tutorial if you just want to get shallow understanding.
You’ll need some hardware components to compete the tutorial, here is the list of parts.