How to stream Amazon Prime Music

Does anyone know how to stream Amazon Prime music?  I can play Amazon prime music using my PC but how can I stream it through the USB port so I can play them using my USB DAC?
How have you configured the sound output for the PC?  In the settings area have you designated the DAC as where you want the sound to be directed, instead of the internal Computer Speakers?  Do you listen to other music from the computer via the usb connection?  If so then you may have to check the setting within Amazon.
Actually this is going to be my first attempt in streaming via the USB DAC so my questions may appear to be naive.  I currently have a laptop so I guess it has a built-in sound card, but I can try to see if I can direct the audio stream to one of the USB port.  To me, conceptual it is rather simple but I don't know if the PC has the hardware implementation for it.I am just curious?  Could you describe your PC setup for USB?
So based on your suggestion, I did a quick search of "how to direct sound from labtop to usb port".  It turns out to be rather simple.  First I need to purchase a USB DAC.  Plug into one of the laptop USB port.  Go to control panel and select the USB DAC as the default playback device.  At least that should work in theory.Now that the USB DAC is the default device, either streaming through Amazon Prime or anything on the laptop would go to the USB DAC. 
Correct. You may need to install a driver since you are using a PC. The DAC you choose will specify this. In some cases Windows will offer up the appropriate driver.
I’m a bit confused, because your original post seems to imply that you have a DAC that connects to your PC by usb, but one of us seems to be missing something...Anyway, my setup is I have a Mac Air that is connected to the usb input of a Bryston DAC3.  I had to change the sound settings in the Mac to designate the Bryston as the desired output instead of the Computers internal speakers.  It’s been a while since I’ve used a Windows PC but they have something similar in their control panel, and as the last poster mentioned with some DACs Windows Computers need a special driver installed.
  I hope this helps

In fact, it’s not easy to get the conversion of Amazon Music due to DRM protection. As we all know, Amazon Prime Music is a streaming music service that gives you the ability to download songs for offline listening. But all downloaded songs are cache files only available for Prime subscribers.In this case, you can try Amazon Music Converter to convert Amazon Prime Music to MP3 then save then on USB .

In order to stream Amazon Prime Music, I use the Amazon Music Converter from DRmare to convert and download Amazon Prime Music to MP3 first as the local files. Then I can move Amazon Prime Music to play on any device and platform I want.
Amazon Prime Music allows you to stream on the PC and other authorized devices directly. But they are cache files like other streaming music services. If you'd like to stream Amazon Prime Music to a USB port, the best way is to download local Amazon Music to USB in advance. 
To get offline Amazon Prime Music, please install and download Amazon Music Downloader on your Mac or Windows computers, and then add Amazon Prime Music to it to download as common tracks. 
After that, you can transfer them to a USB and play them on all devices that have a USB port. 
Bluesound / Node has good Amazon HD playback, I've read. You can integrate an Alexa device into the  Node for voice commands. Amazon doesn't play with mfrs that don't integrate Alexa into their devices. I used to be able to stream Amazon HD from the phone app to my Chromecast Audio puck which is plugged into my DAC/preamp, but Amazon locked that device out. They're control freaks. :(