Can't sync local music to my mobile

[SirJollyWally]

I've done what all the guides say to be on the same network and then put the local song in a playlist and then set the playlist to "Available Offline" but when I do this with a playlist only containing local songs a grey arrow appears next to the playlist and says "waiting to download" but the arrow does not appear next to any of the songs so it just says "waiting to download" forever.  The only reason I can think of that it isn't working is because my desktop doesn't have wifi capabilities so it is plugged directly to the router through a eithernet cable.  If anyone knows whether it's my computer or something else, help is apriciated!  

P.S. Sorry if my grammar is horrible.