Ok in Roon, go into Settings, then Storage
Select ‘Add Folder’
Then ‘Add Network Share’
You then need to add in the network details of your NAS, including the directory you wish to connect to that contains your music files.
You will see that use hostnames of my NAS units ‘dingo3’ being the main RAID1 volume, ‘dingo2’ being a supplemental (and part backup) RAID1 and not connected to Roon, unless they fail, is dingo4, as a complete backup in RAID1, and dingo1 as a legacy JBOD NAS.
My main folder is called ‘Media\Music’, but I have two other storage locations for MQA & DSD duplicates & formats not supported by my legacy UPnP server, which also still scans the NAS volumes.
Once you have added your network location of your folders Roon will start to scan them.
Also you will need to check the ‘Automatic Rescan Interval’ as NAS units don’t always let Roon know that changes have been made.
Does that help?