If you do not know your secret code for your Google account, you can find it by opening the Google account website and selecting 'Security.' In the 'Security' area, scroll down to the section 'Signing into Google,' and click the '2-Step Verification' option. Unless you have already enabled 2FA with a mobile device, you may need to sign in again at this point. To set up Google authenticator for PC, scroll down to the 'Authenticator' app section and click 'Set Up.' The secret code associated with your Google account will appear in the box below, which is a combination of 32 letters and numbers.
See also - Google Chrome Users Alerts