I've done this recently - follow the vultr guide https://www.vultr.com/docs/how-to-install-jitsi-meet-on-ubun... then the jitsi docs to secure your meetings as required https://github.com/jitsi/jicofo#secure-domain . Then you can use basic Auth in nginx https://docs.nginx.com/nginx/admin-guide/security-controls/c... to secure the site.