I also bought the instructor's book, but I personally liked Inflearn's lecture better! The explanations were easy to understand and I could understand intuitively. When I learned by Googling, there were so many parts that I didn't understand because the information was too fragmented, but listening to the well-organized lectures made me feel refreshed. I think I need to keep going through the lecture materials and become completely familiar with them. Please send me the lecture materials haenara.shin@gmail.com Thank you!