I think this is a really good lecture for GitHub beginners. And it's free..! Jeong Ho-young, you will be blessed. In particular, it was very helpful to be able to understand it by looking at https://learngitbranching.js.org/. Thank you. However, between lectures 2 and 3, I think there should be a process of writing more content in the hello.md file and committing it with a commit message like 'Add revert changes to a specific file'. There is one more commit that is not in the lecture content, so when starting lecture 3, beginners might have been a little confused.