The web GUI offers an alternative user interface to the CLI. For security reasons, the web GUI is disabled by default — if you want to use it, you must enable it through the CLI.

Aside from that, you can perform any operation through the web GUI that you can perform through the CLI. The web GUI mirrors the structure of the CLI; in particular, the command hierarchy in the web GUI follows the basic CLI configuration structure.

So, if you are familiar with the CLI then the structure of the GUI should be easy to understand.