i have followed the step as given here:
https://docs.openvidu.io/en/2.12.0/deployment/deploying-ubuntu/
hence after accessing it on browser it looks like only
so what steps need to do further ?
You’re trying to use the 2.12.0 version.
Please, use the latest version (2.22.0), several bugs have been fixed.
2.12.0?, good luck 
EDIT: I mean, probably works, but I would recommend to be in sync with current versions, just to avoid possible security problems, bug fixes, new features, etc…
Also newer versions are more easy to deploy. Requires docker but just minimal knowledge and it is easier to configure the entire deployment.
Follow this instructions instead for CE: On premises - OpenVidu Docs