Getting mp3 files from CD-R onto my iPhone via iTunes.

Hi, all. Late adopter here. I finally gave the old dumbphone the heave-ho a couple weeks ago and have my first iPhone (a 5s). I'm just starting to figure out how iTunes on my desktop Mac works with the phone. My first priority is the following, but I can't get it to work:

I'm taking a foreign language course, and have a CD-R of 14 mp3 files of pronunciation lessons that our teacher recorded. I want to get these onto my phone for listening and practice on the go.

I made a playlist in iTunes of all the 14 tracks, but I'm stuck there. I just synced my phone, and iTunes on the phone now contains the one album I purchased a couple years ago (plus that &%^&* U2 album, of course) - but that's it. I can't see anything in iTunes on my desktop to indicate how to tell the phone to import my language lessons playlist. Neither googling about for solutions, nor the Help function in iTunes, have helped much.

I don't quite understand why it can't be a simple matter of dragging and dropping some file icons, the way this sort of thing has mostly been done since personal computing started. Oh, well... brave new world.

Specifications: OS 10.7.5, with (I think) iTunes 12.1.2.27. iPhone 5s with iOS 8.1.3.

Thanks, everyone!