The first thing you have to do is to set the playback options. From the menu select MPD and select your d/a-converter. The RaspberryPi Analog Out sounds horrible, but might be used to see if RuneAudio works at all, before a proper d/a-converter is connected. The HDMI Out is a good option for use with an AV receiver. If you have connected a d/a-converter using USB, chances are that RuneAudio already has selected it. For playback of ALAC you need FFmpeg decoder plugin set to enabled and if you use a d/a-converter that can play DSD files, also set DSD support to enabled. All the other options on this page are well documented right below the settings. When in doubt, don’t change the setting. If you have changed anything, press Save and Apply. The next thing is to tell RuneAudio where your music is. If you use a USB drive, it will already have found it but if your music is on a network share, you need to tell RuneAudio the network address. To do this, go to the Sources menu and click on Add new mount. Source name is only for your reference, so you can use any relevant name like Computer in the attic. The fileshare protocol depends on the computer the share is on. For Windows and some NAS’ses use SMB/CIFS, other NAS’ses might need NSF. Shares on an Mac initially were a bit of a problem. It took me a lot of time to find out that since OS X 10.9 Apple uses a new network process called Discoveryd but never managed to get it working properly. Apple in 10.10.4 has switched back to mDNSResponder they used before 10.9. This was also why RuneAudio did work with my old, retired Core Duo Mac mini running OS X 10.6.8. On the Mac, in the sharing panel, you have to set the password protocol to Windows for the user account you will use. Also set the SMB/CIFS (OS X Shares) option in RuneAudio
The next things you have to fill out are the IP address and the name of the share. You also have to inform RuneAudio whether a guest account will be accepted by the computer or NAS. If not, you’ll have to specify a username and password to log in. Don't go for the advanced options and click ‘save mount’. If all went well, you will see the share, mentioned under network mounts, with a green check mark in front of it. In the left lower corner you will see circling arrows and the word Updating, indicating the music is indexed. Depending on the size of your music collection this might take some time (my 8000 albums took hours). After that you're ready to play music.