Libraries in processing extend the code and allow processing to do more. There are 6 libraries that are already built into Processing: video, audio (minim), serial, Network, and a couple exporters. All the other libraries are not written by the processing people, and you will need to install them.
NOTE: some have better API’s and examples than others, but if they are on the Processing libraries page they should work.
In the finder, open the documents folder and then the processing folder.
If there is no “libaraies” folder here go ahead and create one.
When you download a library, from Processing.org or otherwise, place it in this new libraries folder and re-start Processing.
Now if you open processing and go File > Examples you should see examples of your library in the “contributed Libraries” section of this window.
– Minum – sound library for playing back sound, synthesizing sound, etc. It comes with processing but here is the reference: http://code.compartmental.net/minim/
– Many more Processing Libraries here: https://processing.org/reference/libraries/
The minum library enable us to put sound to our sketches. It has many classes but a simple one to play back music is the Audio Player class. See the example to see how to play an mp3 file with your sketch.