Based on the Audiostream review in Mike's post it looks like all you need to do to use a NAS is to connect it and the Mini wiill auto detect and set up all by itself.
"Network setup is relatively simple due to the Lightning app's setup guide. Plug in the Mini, connect it to your network (the company recommends WiFi), and follow the guide in the app. This process should take all of a few minutes as the app auto-discovers your WiFi network, your Aries device, and once connected, your NAS. The first time you connect to your NAS the app will take some time to scan your library, the exact amount of time depends on its size."