First of all, there is a comprehensive knowledge base on the Roon Labs website. It is a good start for beginners, to learn about the software.
If you are having trouble with Roon Server on your NAS, there is a friendly and helpful community on the Roon Labs forum (including me). ASUSTOR, QNAP and Synology devices have their own category there and are also supported by Roon Labs. If you have any issues you can visit the support section of the Roon Labs community board. For general questions regarding the usage of Roon Server on NAS devices, write a message in the ASUSTOR/QNAP/Synology section. Of course, there are other interesting topics on their board and it Is absolutely worth a read.