You will need to have the git version control software installed to download this book's code.
git is available from https://git-scm.com/download. A handy GUI-based installer is provided, and you shouldn't have any issues getting it working. When installing, be sure to check the option for adding git to your PATH. This is shown in the following screenshot:
After git has finished installing, you can test it by opening a new command window and entering git --version: