Hello chwinter
There are 2 possibilities:
1) Streaming with Bluetooth - you can stream audio from your smartphone or tablet to the Evoke via Bluetooth (more info can be found in the manual, page 14).
2) Audio streaming from a PC, Mac or NAS - either install a multimedia server on a PC or Mac (there are many free of charge, e.g.:
https://en.wikipedia.org/wiki...) or buy a NAS (Network Attached Storage) with a built-in multimedia server (keyword UPnP server/DLNA).
Have fun with it ;-)
Michele