Missing a brief overview of how it works and a short demonstration

You might not believe it:

Today is the first day that I have read about processing.
So I looked up the homepage.

Lot's of information but nowhere I could find a still brief description that goes beyond

"Interactive programs with 2D, 3D, PDF, or SVG output"

aha. --- .. --- ... --- ... and how is it "processed"?????

Do I click drag and drop graphical objects that represent computing commands?
Do I write a programtext? similar to which programming language?

Where can I find a graphic that gives on overview about the main elements used by processing?

The homepage suffers from "experts blindness to beginners diffculties"

まず processing.org のホームページと既存の学習リソースを確認し、簡単な概要とデモをどこに配置するのが適切かを把握します。Processing がどのように使われるのか、ユーザーが何を書いたり操作したりするのかを簡潔に説明し、issue にある初心者からの質問に答える短いデモを追加すれば完了です。