The page you are following doesn’t include the instructions to install the GitHub CLI, so it is likely you don’t have it installed (it doesn’t come with git as far as I know).
Installation instructions can be found here: https://cli.github.com/
The page you are following doesn’t include the instructions to install the GitHub CLI, so it is likely you don’t have it installed (it doesn’t come with git as far as I know).
Installation instructions can be found here: https://cli.github.com/