Great, concise resource to learn LLM technical fundamentals?

Can anyone recommend a great, concise resource to learn LLM technical fundamentals including transformers, pre-training, fine-tuning, etc from the ground up starting with neural networks?

The resources I can find are either how to use langchain to write LLM apps, which is not what I want, or very deep graduate level book study, which I don't have the time for.

Something that starts with neural networks (which I am familiar with) and takes you all the way to how LLMs work, but as concise as possible.

My goal is to be able to talk about LLM technical fundamentals cogently, not necessarily code one from scratch.

Thanks!