Ok so I did edexcel too basically I just listened to the set works loads while looking at my annotated anthology (book with the scores) as well as making mind maps and doing revision questions on the set works. I would go on the edexcel website and look at the past papers and see how the questions are worded so you know what to expect in the exam, maybe do a couple. In terms of the 12 marker, don’t worry I’m sure you’ll eventually learn how to do those in class, I’m pretty sure before my exam I’d only done maybe one or two of those essays so I didn’t know what to expect but I did fine in the end lol. At this point it’s more important to know all the content and to really consolidate all your knowledge than learn how to write and structure an essay. Good luck !