You only need an access code to create a new account if you don't have an existing account. Your account username is typically your district (or organization) email address. If you don't remember your password, click "Forgot Password", enter your email address, and follow the instructions to reset your password. Once your password is reset, you can login with your email address and new password.
If you don't have an account, you can check with your principal or supervisor, or submit a support inquiry.