This category is not really for asking about these types of things. Instead of asking how someone else is doing something, ask about how to do specific things. Please also be sure to attempt to code what you need first before asking!
The movement of the circles is tweening. Tweening is best performed with the TweenService. I would assume that the developer has a loop that handles the placement of these circles respectively (alternating between a line pattern and a square pattern, or handling each position separately to form these shapes).