Hello,
usually, you don't install Alfresco on a NAS, but make it use one for file storage. The NAS server itself appears to weak to host a rich server application like Alfresco. In order to have Alfresco (running on a separate system) store content on the NAS, you usually mount the NAS as a drive on the Alfresco server via CIFS / NFS (depending on OS) and use the standard alfresco-global.properties configuration for "dir.contentstore" and "dir.contentstore.deleted" to point Alfresco to the NAS drive for storage.
Regards
Axel