How do I download songs to an iPod Shuffle/Nano?

Hi All!

As the title suggests, I'm wondering how to download songs to an iPod. Right now I'm using my iPhone, which, all though it can do everything I need it to music wise, doesn't have the charm of the iPod. I really like the square Shuffles and the Nano 5,6, and 7.

I currently use Spotify, and I have NO clue how iTunes works. Will I need a paid Apple Music subscription to download my songs? Can I download them from Spotify? Please advise.

Thanks!