Enter the website and the current code from Google Authenticator. You receive one owner product key, plus the env line for that install.
For a live shop, enter the domain only, such as shop.example.com. On your own computer, enter localhost. That covers 127.0.0.1 and a private address like 192.168.1.10, and it does not use up the live website.
Open Google Authenticator and enter the current 6 digits. Each code works once.