Click the green flag to start. A shape will appear on the grid automatically. Click on the button you think correctly corresponds with the shape on the right hand column. If you get it right, it says "good job," if not, it tells you what shape it is. This process will go on forever.
I used the "Learn to Program with Scratch" book to complete this game. I first had to download the file "Ch 9 QuadClassify NoCode.sb2." I then followed the book to make 2 make a blocks and one script.