i have followed this url to https://docs.openvidu.io/en/2.13.0/deployment/deploying-on-premises/
i just rename the docker-compose.override.yml. when im browsing the my domain the site showing like this 
and i followed this url https://docs.openvidu.io/en/2.13.0/demos/openvidu-classroom/ for classroom app.
i have clone the app in /opt/openvidu folder. but stuck how to run the classroom app?
First you have to compile and package classroom app in a fat .jar or a docker image.
Then, you have to configure classroom app to be executed in the same machine as OpenVidu platform. If you dockerize classroom demo, configuration is very easy, just configure all containers in docker-compose.override.yml.
If you want to use fat.jar is a bit more complex as you have to configure some sort of mechanism to start the application on boot.