although i don’t take history extension, your notes should always be taken according to the syllabus. make your notes around them as they’re the only information you’ll need for your assessments
have a big set of notes of historians and their views (categorised by what school they're in/who they have debates with) and then for your case study, structure it in terms of each debate as the heading (eg 1A Napoleon was a military leader, 1B Napoleon was not a military leader, 2A Napoleon was a reformer, 2B Napoleon was not.... and so forth)