Download Processing tool- https://processing.org/download/
Steps(For windows)-
- After download extract the file.
- Open the file, and click on the processing application file.
- The processing software will open, click on the mode in the upper right corner which is by default selected for Java.
- Click on Add Mode.
- Select Python for Processing 3.
- Click on Install button which pops up below.
- Python mode will be selected, and than you can run the attached sketch file by clicking on the Play button.