Adding more playlists to the Wiwoo Sport Clip?

A while back I bought my roomie a Wiwoo Sport Clip because she wanted a simple player with bluetooth and shuffle (p much her only criteria, mine was that it doesn't connect to wifi), but I liked its compact size and simplicity so much that I exchanged my Phinistec Z6 for it (she decided she liked that she can play videos on it, even if low quality). I like that it has a playlist function, but there are only three playlists and I can't find an instruction manual for the Sport Clip anywhere online (the one it came with is long since lost), or any tutorial to add to it. When I plug the Wiwoo into my computer, the files are only for the regular music slots, (Artist > Album > Song, etc), nothing for any of the playlists to add more to.

I like making silly playlists based on whatever thing strikes my fancy, and I've already used up the three allotted to me. When I tried adding them as their own "album" (something I did on the Phinistec because I didn't even realize it had a playlist option until trading, that thing was so frustrating to use the regular music app on that I just played music from the Folders), the music I had adding to that "artist" (labeled "X Playlist"), it duplicated the songs in their original sections (like two Strawberry Blonds in the relevant Mitski album) which was annoying.