Aurender media servers are available on the local area network as an Apple AirPlay receiver (also known as an endpoint). When using an iOS device or a Mac running a recent OS X version, any audio coming from a program or App on the device may be streamed directly to the Aurender.
AirPlay is accessed on an iOS device by swiping up from the bottom of the screen and tapping the AirPlay button, where available AirPlay receivers are listed, as shown in the screen capture below. Please note that while an iPad screen capture is shown, an iPhone operates the same way with AirPlay.
If you use a Mac computer with OS X, and wish to stream audio content from a program or web browser, you can hold the "Alt-Option" key and click the "Speakers/Sound" icon in your top menu bar, where "Output Device" will be an option.