The phrase "to open the chapter" means to begin a new stage or part of something, usually referring to a book, story, or a period of time. It signifies the start of a fresh and significant section. Full definition
You can enable the advanced features of search functions by finding the keyword in open chapters only, look for letters that are case sensitive, and find the whole words only. (bbebooksthailand.com)
Here are 11 tips for creating a strong opening chapter for your book. (tumblr.com)