The 390 is a Roon Ready endpoint. To use Roon, you should
Install Roon on a PC. This gives you both a Roon graphics control portion and the RoonServer.
Have both the PC running Roon and the Mind 390 connected by ethernet to your home network.
Login in to your streaming service in Roon under Settings/Services
Under Settings/ Audio find the Moon 390 in the Roon Ready section. Enable it and give the audio device a name. Then choose it to be the active Roon Endpoint.
Choose something to play ensuring that any settings on the Moon for Roon use have been enabled.
Further on you can
Install Roon Remote on your phone or tablet to control the RoonServer running on the PC
Setup Storage locations for local music to add to your library