Linking accounts

I wanna log in my Facebook with this quest account but I can’t. It says I can log in my fb through the NBA Live settings but I can’t see anything to do that. Then when I log out, and sign in facebook with existing user, it says there were no existing users On fb. Please tell me how to sign in facebook with guest account?

ChickenIsTasty about NBA LIVE Mobile Basketball, v2.1.4