Neural Networks from Zero to Hero

https://karpathy.ai/zero-to-hero.html

Just watch the first lecture and you won't be able to not watch the rest. It starts with making your own autograd engine in 100 lines of python, similar to PyTorch and then builds up to a GPT network. He's one of the best in the field, founder of OpenAI, then Director of AI at Tesla. Nothing like the scam tutorials that just copy-paste random code from the internet.