This might depend on the level of detail you want to show.
As i asked earlier,
What should they be able to "take away" after seeing your material?
Until you decide exactly what "they" are to learn, it is possibly premature to pick the presentation method.
If i was going to show some program to beginners, i would probably "walk" them thru the code routine by routine, explaining why each part of the code was written. I would probably not speak to every line of code, but rather the functionality of why that part of the code was written. If there were questions, individual lines of code could be discussed.
I tend to do this sort of thing with a large white-board available so that particulars can be shown when asked rather than needing some document that "has it all".