The speech is too slow. (It's frustrating, so I listened at 1.5x the speed.) And although it says that it's easy for beginners to understand, it goes by too quickly... It feels more like it's showing rather than explaining? Just looking at it and reading it quickly? I feel like there's not enough of a clear explanation of why this part is important. Fortunately, I was able to understand the parts I didn't know about blockchain through the PDF, so um, those 2 stars are my evaluation of the PDF...