User name or email is "admin" as default (We can change the user email).  when you create the DB you give the password of the admin, same password is enter here, and you can login as Administrator.     You can change the password after login, go to settings and select the user, from there you can change the user password from the more button.      we can change the email from there directly..

To change admin password.

    from passlib.context import CryptContext
    print CryptContext(['pbkdf2_sha512']).encrypt('MY_PASSWORD')

    UPDATE res_users SET password='', password_crypt='HASH' WHERE id=1;