You will see a list of available macOS Versions to download (Please note: Mac OS X Lion and OS X Mountain Lion cannot be downloaded here. This is planned to be fixed in a future update.)

To choose a macOS Version to download, press the number it corresponds to and then press the (return) key.

The script will ask for confirmation. If you selected the incorrect macOS Version, press the (S) key to choose a different version.

If you do not see your version listed, press the (9) key and then the (return) key to see the next page.