How do I set default "server"

Server Version#:1.21.1.3876
Player Version#:

I reinstalled Windows and Installed Plex fresh, and it’s all very different to the way it was before, even though I was using the same version prior. One of the annoying things, is that now Plex by default shows a library which seems made up of content that isn’t mine, general meta content crowd soured called Plex. I have a Windows Server called Networkn and that is the only content I want displayed, or at the very least by default. Can I control this via the Server, for all clients, or do I have to do this per client? I am primarily using either the web client, or the FireTV client.

You can disable online media sources for your account @ plex web, settings, online media sources.

You cannot control the online media sources for other plex users that have their own plex account.