This Code Your Own Games book that you are commenting on is by far the one my kids have enjoyed the most. By doing all the tutorials in this book, they had the skills to design their own Scratch games.

Yes! This book is all we used to get started. Everything is done on the web. There is no software to install. There are some instructions in the book, but all you need to do to get started is go to scratch.mit.edu and click the Create button at the top. From there, you can get started with the first game tutorial on page 12 called Hungry Cat. There are a few pages of intro before that, but honestly, I’m pretty sure my kids skipped it! If you want to save your files, you will have to join (for free) by creating an account, which you can also do from the top menu bar. Feel free to reach out if you have questions!