A comprehensive overview of how to understand, train, and deploy large language models (LLMs), powerful AI systems capable of processing and generating human-like text. The guide begins by defining LLMs and their key concepts, then covers setting up an environment, collecting and preparing training data, selecting appropriate LLM architectures, and training the model itself. Further chapters explore how to fine-tune pre-trained LLMs for specific tasks, deploy these models for real-world applications,