https://disconnect.me/trackerprotection
Two-factor authentication helps protect your account if someone else tries to log in. When there's a login from a new device or browser, we'll ask for a login code or other verification method to confirm that it's you. You'll need to set up two-factor authentication to keep using Facebook.
Alla svar (1)
2 Factor Authentication Support Page
Here is the page to setup 2FA. I. Your account, you will have to first disable it, then set it up again. When it says to download your file, copy the first code before you click "continue".
Also, it helps to have the 2FA app open because if you close it, the page you are on will close and you will have to start over. I use the app switcher to get back and forth to prevent this.