Hi Paul,
Have a read of the Importing content from Meridian/Sooloos Systems topic.
Performing a Sooloos native export to a storage location of your choice is the best way to get your Sooloos library in a format that Roon can use.
The storage location of the exported files could be as simple as a USB connected hard drive, though a lot of us on here use a NAS (I use a intel powered QNAP NAS as that also compatible with Sooloos).
You can run Roon on either a Windows or iOS PC or server that support the OPEN GL3 graphic standard (most modern graphic cards do, but it worth checking).
There is also a headless version of Roon call RoonServer as this does not a user-interface OPEN GL3 is not required. Though would still need Roon (running as a remote) on another OPEN GL3 platform to be able to control it. This again could be a Windows, iOS or OSX or android.
Have a scan in the Frequently Asked Questions category there lots of info in there about Roon.