The tutorial follows the Algorithmic Thinking Model (see the December 2012 post, Algorithmic Thinking) that teaches that programming (or, to use the current term, coding) is a set of skills and not a single skill.
View this short video that shows one of the Scratch scripts discussed in the tutorial. In the video, an ant chases a mouse-pointer as the pointer is moved around the screen. The distance between the ant and the mouse-pointer is computed using the distance formula.
You can obtain a free copy of the Distance Formula Tutorial describing how to code the distance formula to create the script seen in the video by sending and email request to firstname.lastname@example.org.