I recently tried to create a playlist for my USB stick, and failed. I asked WD for support on the matter, but really didn’t get the answers I was looking for. That said, in case other people need this:
An easy format to use is .m3u playlist format. Refer to Wikipedia for more details.
Playlist formats that are created from your computer are file relative to the computer and need to be edited to be file relative to the USB (or other) drive.
For a directory such as:
music (top folder)
doors (second level folder)
place the .m3u file in the music folder and relative to that location, the file contents should be:
To add additional songs, create a blank line after the first entry and add additional songs as you wish:
Allman Brothers\Anything Goes.mp3
Allman Brothers\Jelly Jelly.mp3
#EXTINF:0,The Wine Song.mp3
Youngbloods\The Wine Song.mp3
If you use Windows Media Player, easiest way to create an m3u playlist is to either create a new playlist or using an existing playlist, right click it to find the location that WMP is storing the playlists. Then create a new text file in that folder and rename it to MyPlayListName.m3u
You can then drag songs to your new playlist, and after you are done, edit the relative paths per above.