The interactive lessons in this repo are to be used with Bert's Interactive Lesson Loader, the desktop app here bert.bill.
Every lesson rendered through the app includes a web-based terminal emulator component that allows for practicing the lesson material.
These web terminals are embedded in the user interface, available at its footer and as a slide-in from the right (click Utils to reveal).
Please consult the bert.bill project for details on architecture and configuration.
With that said, from here on out I will make the assumption that your web terminal connection is ready and accepting connections from your computer.
You'll see plenty of error messages otherwise :)
For every lesson, you'll notice that as you scroll down the lesson material, a terminal window will appear, allowing you the opportunity to practice live commands against a sandboxed environment.
You need only click a sample commands to send the input directly to the terminal for execution.
This is similar to the experience you get with Katacoda and Play with Docker.
Do read through the commands, do grok them, and do try them out!