I was using Roon with an Ultrarendu. When I sold the unit, I discontinued Roon. I now have a LUMIN D2, and re-subscribed. Using Roon with the Sonore product was pretty much intuitive, which is good as I am something of a techno-moron. At this point, I am unable to even enter the Room system, as I can’t get past Configure Roon Core!
The actual message that is repeating is “Looking for Roon Core”.
What exactly do you have that you are using with Roon? Just the computer and the Lumin? How did you use the ultraRendu? If you are trying to just use just the computer you are on you need to set up a Roon core on that computer.
Ultrarendu connected to internet via Ethernet, with IPhone as remote.
Where were all your music files stored? Do you have a computer now that has all your music on it? That is where your core needs to be
I use AirPlay and Tidal.
Ok. You still need a computer with Roon core installed on it to use Roon. When you had the ultraRendu you would have had Roon Core installed on a computer or network attached storage like a Synology. If you can’t remember what you use that is fine but you need a computer that you can install Roon Core on. The computer has to be on to use it as a Roon core as well
So, I need to download Roon on my desktop computer? Downloading Roon on the iPad is not enough.
Correct. That computer becomes your Roon core
When I go to the APP Store, it tells me that I can only download Roon on my iPad or iPhone.
To install Roon on your desktop you can download it from here Roon Software Downloads - PC, Mac, Linux, Android & iOS | Get it Now and you will see a button that says “Download for MacOs” or “Download for PC” depending on which you are using
I chose the AppStore download.
I am now doing it right.
yeah it is confusing at first since it works differently than everything else. Lol, I was so confused when I first got into Roon 
but after using it for a few days I figured it all out. It will make sense soon enough
I should also mention that if you have not already done it, you should sign up for an account. You will need to sign into an account to set up your Roon core
Got Roon set up, but now the network doesn’t recognize the lumin
Yes, I believe so.
What do you mean? Is that a message in Roon? if you can go to settings and then to audio settings and see if the lumen device is showing up. The lumen It may need to be restarted.
After restarting the computer, Roon does not appear in Finder.
It should be in the applications folder on your hard drive, no?
It does not have an icon in Launchpad. It had to be downloaded again.
If you installed it, then it should already be on your computer. I can try and walk you through this after dinner a little later tonight if you want