Hey, when you just created your account you won't have two-factor authentication set up yet, therefore you will leave the Google Auth Code field empty.

But generally, you go into your account settings to enable two-factor authentication via Google authentication. It will display a QR-code for you and a key (the QR-code is just an image form of the key)

Download Google Authentication on your smartphone, open it up, create a new account via QR-code scanning or manually typing the key in. Pick to scan via QR-code, when your camera is activated you scan the QR-code shown on the website you enabled it on.

Now you will have a listing for that website that will display a temporary numeric code that you have to enter in each time you login to your account.

Hope that helps you!