If your command line indicates that git is not a recognised command, you must configure your PATH.
Check to see where git for windows was installed. If you didn't change the default settings, it should be installed in C:\Program Files\Git\bin or C:\Program Files (x86)\Git\bin.
Press windows to open the start menu and search for PATH.
Select Edit the system environment variables, and then click Environment Variables.
Select Path, and then click edit. Select new, and paste C:\Program Files\Git\bin or C:\Program Files (x86)\Git\bin, depending on which folder exists.
Open a command line interface and check if PATH has been configured correctly by typing git and pressing enter. If so, continue following the steps in the tutorial.