I didn't add songs to playlists but I downloaded them for offline play, how do I access those?

[lizthree]

I loved last weeks Discover Weekly playlist. I didn't know I needed to add them ('+') to my playlists, I thought downloading them all for offline play would be enough to save them. Monday rolls around and my Discover Weekly playlist changes... I want to see all the offline music that isn't necessarily added in 'My Music' (songs, playlist, albums,...etc). Can someone help? I actually have iOS, Windows, and Mac platforms that I listen on...

Thanks!