About UPnP AV
UPnP AV is an open industry standard for playing digital audio (and other media) over a home network. In a typical setup, there's a music server that stores and indexes your music, a music player that plays digital audio data through your amplifier and loudspeakers, and a control point that lets you browse your music collection and select music to play. The control point sends your selections to the music player (either one at a time or as a playlist containing several items), and the music player reads the audio data from the music server and plays it for you.
If the server, player and control point are all built according to the UPnP AV standard, they should work together even though they may be produced by different companies. This gives you flexibility to mix and match the digital audio components in your home network, just as you might mix and match a CD player, amplifier and loudspeakers in a traditional audio system.
There's another standard named DLNA that's very similar to UPnP AV. If a component in a digital audio network supports DLNA, it should be compatible with other components that support UPnP AV, and vice versa.
Setting up a UPnP AV system
If you want to use MinimServer as your music server, you'll also need to have a UPnP AV control point
and a UPnP AV music player. You could use free software running on a PC for either or both of these,
or you could use specialized hardware components. A typical setup might have the following:
Music player: a dedicated network audio player connected to your home audio system
Control point: an application running on a PC, Mac, iPod, iPad or Android device
Music server: a computer or a Network Attached Storage (NAS) device
There are many different options for each of these components, ranging from free software applications to dedicated hardware components with a wide variety of price tags. As a starting point for finding out what's available and suitable for your needs, you could take a look at this Wikipedia page.
Importance of the music server
The control point doesn't access the audio files in your music collection directly. Instead, the control point displays your music collection by accessing a browse tree that's created by the music server from tag information in your audio files. The browse tree provides a series of choices (for things like Album, Artist, Genre, etc.) that you can make in a given order to find the music that you want to play. There's no UPnP AV standard for what the browse tree should look like, so there could be big differences in the browse trees that two different music servers create from the same music collection.
The control point application controls the appearance of your selection display, but the content that it shows you is limited to what it finds in the browse tree. Because the content of the browse tree is controlled by the music server, your choice of music server can make a big difference to how easy it is for you to browse and find music in your collection.