Whoops. She forgot to explain how chakra moves within the body, apparently! This ties into 'why handsigns.' She dregs her memory for the old lecture (she remembers more than she thought; she had to practice this pretty thoroughly for medical jutsu) and explains the Gates, and how chakra clusters and flows in lines in the body, and the points where it's easier to force chakra from your body - or block someone else's through careful injury.
...Unfortunately charcoal-on-wood isn't a good medium for drawing fiddly detail like the chakra lines. She can try a very rough sketch on a particularly large piece of wood, though.