Hello!
In order to understand the structure of this story, I will provide you with some guidelines:
The sisters, Danielle and Christina, live separate lives where as the story will follow them individually in each chapter. This means that chapters beginning with "Danielle" follows her and her story, and the ones marked "Christina" follows hers. However, their paths will cross in different chapters, so it makes sense to read it all.
Second of all: I do not speak English as my native language. Therefore there might be some incorrect spelling and grammatical errors :)