I'm trying to catch up with AI but it's difficult because most articles I find are kinda vague and there is a lack of clear examples.

It's always about prompting or how AI "is great" yadi yada but hardly any step by step examples.

I can easily ask gemini CLI to produce code for example. But how to work with AI in an existing codebase isn't obvious at all.

It seems also that for any serious use you need a paid subscription? It seems like the free models just can't handle large codebases.