The UX field has been doubly impacted by AI: we are challenged to design for AI systems, and we also encounter AI integrated into all the tools we use — whether we want it there or not. Understanding how AI really works is therefore twice as important for us. This will be a highly accessible explanation of how LLMs work under the hood, to help UX designers, researchers, and leaders gain fluency in AI functionality so that they can base their decisions on fact rather than hype.