>And worst of all, why can’t I use newline characters in my chat prompts?

You can, just hold shift and press enter. Like many other text input elements in numerous applications.

As far as documentation and how to modulate behavior, you are human. You should be smart enough to understand and figure out that AI systems of today are still young with equivalent intelligence of a teenager, as you suggest. Use your soft skills as a human, lest today's AI turns you into an example of Roko's basilisk in the future.

More generally, if you want to learn how to use ChatGPT, you should learn how to use a language model, because that's exactly what it is.