Copy the contributed library's folder into the libraries folder at this location. You will need to create the libraries folder if this is your first contributed library.

By default the following locations are used for your sketchbook folder. For Mac users the sketchbook folder is located inside ~/Documents/Processing. For Windows users the sketchbook folder is located inside folder My Documents/Processing

Let's say you downloaded a library with name theLibrary. Then the folder structure of this library inside the libraries folder should look like the one below. The top folder of a library must have the same name as the .jar file located inside a library's library folder (minus the .jar extension):

Documents

            libraries

                  theLibrary

                        examples

                        library

                              theLibrary.jar

                        reference

                        src

Some folders like examples or src might be missing. After a library has been successfully installed, restart Processing application.

Still having trouble?

In some cases the top folder of a library does not exist after extracting from the downloaded zip file. In this case, the top folder must be created manually and given the same name as the .jar file inside folder library. After creating and renaming the top folder, move all extracted folders from the zip file in there.

For example, you downloaded the library theLibrary, then your folder structure should look like this:

theLibrary

      examples

      library

            theLibrary.jar

      reference

      src

now move theLibrary folder into the libraries folder and you should have a folder structure like this

Processing

      your sketch folders
      libraries

            theLibrary

                  examples

                  library

                        theLibrary.jar

                  reference

                  src

After a library has been successfully installed, restart Processing application.