Trying to download a soundtrack from spotify on desktop to samsung s9

[Squidcub]

Premium, na, galaxy s9, windows 10 and android version 8.0

Downloaded a soundtrack from Amazon music a while ago and have been trying to troubleshoot myself on how to get it on my phone. Successfully  got the files onto my spotify on my desktop and have followed all the steps i've found online to try to download it on my phone. 

I put the album in a playlist on my desktop, went to the playlist on mobile, turned on download songs, i'm using the same internet connection for both devices. It's just been saying "waiting to download" for around 20 minutes.