You need to knwo the basics of the Holocaust. Once you know that, learn the different perspectives. Mainly the structuralist and intentionalist (and just know the 'synthesis' approach). Also be aware of the holocaust deniers and relativists although I dont think there will be questions from that.
For the exam, the question is always "What can you learn from this extract about the interpretation and approach of the historian who wrote it? Use the extract and your knowledge of the Holocaust to explain your answer."
So basically first read the extract twice. Understand the perspective. Is it structuralist or intentionalist?
Then start the essay with a general introduction on the topic. Prepare this before hand. Like 2-3 lines. On what the holocaust was, how it is one of the most horrific events in history..killing around 6 million Jews etc.In the next para, or as part of the intro, mention how there are mainly two perspectives in this and brielfy explain this. Also suggest a few names of historians from each of these perspectives.Then say what perspective you think the historian who wrote the text is.In the following paragraphs, quote evidence from the extract which shows the historian's perspective (this will be easy once u understand the difference between structuralists and intentionalists.) and just explain. Wherever necessary, add you knowledge about the holocaust as well.P.s I dont know if this is the best essay structure but it's what i practiced. Anyone who knows more about this paper, please comment and share your views.