To turn on 2FA you need to log into your account and click SECURITY in the dropdown menu.
Now turn on the Two-factor authentication.
Scan the QR-code in the pop-up window with the two-factor app in your phone or put the validation code in the field below.
Press Enable 2FA - now your account is protected with Two-factor authentication!
Use your 2FA app to get the validation code for signing in.