The graph mapper component is a little unintuitive and it's not as dynamic as, for example, a number slider, to modify it you need to double click it, and then you can adjust its values, the problem is that if you change the input values you'd have to re-adjust the domains in the graph mapper in that way every single time; the default values are 0 to 1 in X and Y axis, so, it's easier to provide this component with numbers between 0 to 1 and that way all you have to worry about is the graph, nor the values. Also it seems like the instructor doesn't know that the range component creates a series of numbers within a 0 to 1 domain directly, you could use that component instead of series and cut 3 components out of the definition.