Processing Download Guide (Mac)
Processing-a flexible software sketchbook and a language for learning how to code within the context of the visual arts.
Follow the link to get to the download screen: https://processing.org/download/
Select Mac OS X
Select Open when done.
Processing should be downloaded to your downloads folder. Click the processing-#.#.#-Macosx.zip file.
Click the Processing application.
Click Open when you get the following message.
Processing will open.
Click Get Started to begin.