Installs and run JupyterHub on your instance, offering a convenient way to access it through the web.

The default Authenticator uses PAM (Pluggable Authentication Module) to authenticate system users with their usernames and passwords. With the default Authenticator, any user with an account and password on the system will be allowed to login. See also here

Therefore in order to login you need to use username/password from a local user existing in the machine.