AiMoonsa MP3 player help?

Hey all, got an AiMoonsa device to store music on for long term storage and usage, internet might not be around forever! Reviews seemed good and many said I can make custom playlists/albums to listen to my music on.

But now ive got my hands on the thing, cannot seem to figure out how? Music in folders placed onto device dont appear, only under the ALL SONGS section.

How does one make a custom album?

Thanks for any/all help!