The Story Begins: Why Your Upload Button Is Just The Beginning 👦 Nephew: Uncle! I finally built my RAG system. User uploads a PDF, system finds answers. Simple, right? 👨‍🦳 Uncle: (smiles knowingly) You uploaded a PDF and got an answer? 👦 Nephew: Yes! It works! 👨‍🦳 Uncle: Did you get the right answer? 👦 Nephew: Well... sometimes. Why? 👨‍🦳 Uncle: Because between "user uploads PDF" and "system creates embeddings", there are 15 critical steps. Skip even one, and your...