There is no GUI interface with Roon Server it is designed to run on headless (no display / turned off device) devices running is the basement or cupboard somewhere out of sight.
To configure Roon Server you have to point a Roon Remote at it. This Remote could be Roon running (running as a remote) on a PC or Mac (which may be the same or different machine that’s running Roon Server) or it could be the Roon App available for compatible iOS or Android tablets.
You have a choice to make, either install Roon [Remote] or uninstall Roon Server and just install Roon.
Sorry I don’t know enough about your usage to advise which way is best for you.
Have a read of the Roon Architecture in the Roon Knowledge Base that should help.