01Enabling 2FA
Go to Settings → Security and scan the QR code with an authenticator app. Enter the six-digit code to confirm. From then on, logging in asks for a fresh code after your password.
02Recovery codes
You get a set of one-time recovery codes at setup. Store them outside your phone. Each code works once, and you can regenerate the set from settings.
03Lost access
If you lose both your app and your recovery codes, send a note through the contact form from the email address on your account.