Import local music to phone

[slayne11]

So I have been trying to sync some of my local files of artist that are not on Spotify that I own on to my phone. They show up on Spotify on my PC but then whenever I try to make a playlist or something to add them to my phone the playlist looks blank so I cannot add them. Ive tried downloading the playlist onto my computer so they are "available off-line" but thats not working either. Ive seen a lot of other people have this issue but there have been no solutions that I see. Please help!