Hi,
If you want to use 1500 port, like
https://panel.mydomain.com:1500/ispmgr, it is enough to turn dns A record of domain panel.mydomain.com to your server.
In this case requests are send to ihttpd web server directly. To add SSL certificate put it in the files:
/usr/local/mgr5/etc/manager.crt
/usr/local/mgr5/etc/manager.key
If you want control panel is accessible with address
https://panel.mydomain.com/ispmgr , you need to configure nginx for the domain panel.mydomain.com.
There is an a example in our
documentation
In this case SSL certificate should be added in nginx.