To help you better understand ‘Once’ and the context in which it is set, you need to find some further reading materials – a website, a non-fiction book, a documentary – and read/watch it by Monday.
You need to be prepared to talk about what you read or watched and to evaluate how useful it was in helping you to understand the book. Here are some links to get you started:
You will need to copy these into your search engine. You could also search ‘Jewish children in Poland 1942’ and see what you find.