How to download free music to my iPhone from youtube?

So I want to download this remix of a song that I like onto my phone, but it isn't on the iTunes store. So I converted the link 3 different times and the song plays fine on my computer, but it won't let me put it onto my phone. I tried dragging the song to my phone (which works with every other song) and that won't work. Also, when I put the setting on that allows you to see all of the music on your iTunes on your phone in the music app, none of the versions of the song come up. I was hoping that someone know how to fix it or if there was a better way that I could get the song onto my phone.

Hi, you still need to add your song via iTunes.
1. Drag the song to iTunes library
2. Create a new playlist or add this song to a created playlist
3. Connect iPhone, open it in iTunes, check the Tab music there.
4. You should see the list of playlists for sync. Choose the one you just created and press Apply.
5. The sync should go through now.