This book provides a clear and structured path to building custom GPT using OpenAI’s platform. Each chapter offers practical, step-by-step instruction, including how GPT function, how to build your first assistant, add your own knowledge, enable real-world actions, and apply responsible AI principles. The approach is simple enough for beginners yet detailed enough to support real workplace impact across roles and industries. As you go through the book, you will have the technical knowledge of advanced prompting and the awareness of responsible AI to confidently build and manage dynamic, real-world AI solutions.