The video demonstrates how to install and use Ollama, an open-source tool, to run large language models (LLMs) on a personal machine without the need for an OpenAI subscription or cloud hosting. The presenter, a seasoned software engineer, guides viewers through the process of downloading and interacting with models via the command line and an API. The tool allows for easy access to a library of models, including the compact yet capable “Phi” model by Microsoft. The tutorial covers downloading a model, initiating a chat with it, and using the command line to explore its capabilities. The video also delves into customizing models by modifying system prompts and templates within the model file, which defines the model’s behavior. The presenter demonstrates this by creating a pirate-themed assistant, showcasing the flexibility of Ollama. The tool’s API is highlighted, showing how to programmatically interact with models using HTTP requests. The video concludes with the presenter encouraging viewers to experiment with different models and prompts, and to share their experiences.