Hi, thanks for your question!
The Shiftsound SP plays MP3, FLAC, WMA, AAC and WAV files. For the most reliable playback, we recommend MP3.
You can organise your music in several folders on the card. Navigation is fairly simple, though: you go through the tracks one by one in order, using a long press on + or -. There’s no option to jump to a specific folder or track directly, sorry.
I hope that helps! If you run into any issues with your card, just let us know.