This short lesson introduces “state management” by showing how to change the appearance of buttons based on user actions. Tap a button for example, and the color and/or size of the button can be made to vary based on the fact that it was tapped.
BTW, I ran into a problem with Exercise 1 where it asked to extract a subview from the button. For the life of me, I could not right-click on that button and get the Extract Subview option to appear. The solution is to wrap the button in a VStack and then extract it.