With this kind of tools you don't need to know all the answers, but know how to make the right questions. Giving the appropriate context is part of doing those questions, be with custom instructions, personalities or similar approaches that user interfaces are taking. But it should be something that you can choose and customize for each chat. And, of course, have a library of ready made ones,
Programming is easy. Asking the right question is hard. Prompt engineering is just another abstraction on top of the abstractions we have to get computers to do useful things.