If I start music on my server (which as access to my NAS) - I cannot change anything using my iPhone or iPad. How do i set up dual controls of the Roon without starting over on iOS mobile devices.
Install the Roon Remote app on your iOS or Android devices to control the Core. You can also use other computers as Controls by installing Roon and pointing them to the existing Core instead of setting up a new Core on the new machines.
All devices need to be on the same subnet of your home network. If you have installed Roon Remote and it cannot find the Core, first thing to do is turn everything off and on again. If still no joy then we will shift this thread to Support and get a full network description from you.