Setup for Facebook
After login to your Facebook account, go to settings.
In the security tab, you will find the "login approvals" section. Now you can register your security key by clicking the "add key" link.
After tap the button on your security, you may be asked to retype your password.
When you enable two-factor authentication, your account is protected.
You can also click here to get help about how to add the security key to your Facebook account.