I have forgot the username and password, how to reset for all even though I enter the back up email
From Google Help page Recover your username and password:
If you ever forget your sign-in information, you can go to Google's password assistance page for help.
As you don't remember your username, first select the second option
I don't know my username and click on
continue and follow the instructions.
Once you know the username you can recover your password by selecting the first option
I don't know my password.