It is probably a bit easier to start from a language you are familiar with. That image intentionally is a mismatch of random arrows and operators that don't necessarily align to the semantics of real code.

I think that's one of the things Fira Code's Readme [1] does a better job at than Berkeley Mono's page. The top big image breaks down the ligatures in high level categories or the programming language they are most associated with, side by side the version with a ligature. Further down the Readme you can several real examples from programming languages with the ligatures called out, giving you the context clues of what it looks like in a language you may be already familiar with.

[1] https://github.com/tonsky/FiraCode/tree/6.2