How do LLMs work? Yes there's a model and there's inference, but dig deeper. How can you, today, with < $50, train a small GPT-2 class model, how do you fine tune it, what training data do you give it, how do you give it training data, what algorithms do you use for reinforcement learning, what even is RLHF? You don't have to know any of those details to use ChatGPT, just like you don't need to know how a D flip-flop works in a CPU to write some code that runs on one, but if you're looking for feeling like you know what's going on, at their heart, LLMs are still next word prediction engines, so knowing, deeply, how that engine is created and works, would be my idea of mastery of it. Karpathy has a good set of tutorials on this.