how to configure elasticsearch.hosts?

[kaitaklam]

I am following https://github.com/opendistro-for-elasticsearch/opendistro-build/blob/main/helm/README.md.
I use kibana.yml example to override the values:
When I use elasticsearch.hosts: https://elasticsearch.example.com:443 (from the github page)

the installation is fine and pods are running, but Kibana log shows: the url can't be connected.
How can I find the right url for elasticsearch.hosts?

Thanks

Kai