What is the significance of the first chapter?

The siginificance of the first chapter is its description of Haarlam just before the beginning of WWII. We meet Corrie and her family at a time of joy and happiness; we envision her home, and we see the naive expectations of an entire generation. Unfortunately, by the close of the chapter, the tone changes and we're made aware of impending war, which greatly contrasts with earlier paragraphs. In this chapter, we as readers, come to understand the true threats out narrator will face, as well as garnering a personal interest in the characters of her story and their lives. In other words..... we become invested.