This will be helpful for anyone who didn't know you had to save a song individually everytime you added one to a playlist, if you wanted that song to appear in your Songs category.
- Access spotify on your computer
- Pick a playlist or multiple songs you want to save
-HOLD DOWN SHIFT and click to the FIRST song you want to save
-scroll down to the LAST song you want to save and click it ( this should highlight all the songs inbetween)
-then, while STILL HOLDING DOWN SHIFT, hit CONTROL and click on the LAST song
-this will make a list of actions pop up. Hit SAVE TO YOUR LIBRARY, and that should autimatically save all the songs you highlighted.