Install can be done on same server as servicedesk app, and is almost the same as servicedesk install
Just follow this guide:
https://confluence.atlassian.com/adminjiraserver072/installing-jira-applications-on-linux-828787555.html
For DB:
https://confluence.atlassian.com/adminjiraserver072/connecting-jira-applications-to-mysql-828787562.html
For reverse proxy + docker setup see:
Installing Confluence server in Docker behind reverse proxy