You need to go to the address https://your_server_ip:1500 for authorization in the ISPmanager Control Panel as root or as a registered user.
Login data to the Panel will be sent in a welcome email after the server is activated.
Either the main page or in the "Your ****** Server Options" part of your Client Area.
The root password is not displayed in the Client Area and in the welcome email for security reasons.
You can get the password upon request from the Client Area.