If you have an account already, simply reset your password in the login screen of the new Mytaxflow , after that you need to provide your email address (known in the system) and after that you will receive an email that allows you to set a password

If you don't have an account you need to get this first, you can request a new account via your account manager, email to support@mytaxflow.com or simply create a helpdesk ticket via this link