How do I put music on my Dell Venue 8 Pro?

When I wanted to put music on my Lumia 1020, I just plugged it into my PC with the USB cable and used the Windows Phone app to pick which playlists to copy over. I obviously can't use the Windows Phone app to transfer to a full Windows 8 tablet, and plugging in the USB to my PC don't actually appear to do anything at all.

The Xbox Music app has already populated the songs from my library that exist in its store, which is nice, but that leaves quite a few gaps in my favorite playlists and I can't quite figure out how I'm supposed to get the rest on them on there!