When I begin adding numbered chapters (not all) some of the chapters will add additional subchapters. Also, the Navigator screen has jumped from Chapter 8 to Chapter 11 for some reason. I don’t know what I am doing wrong. Please help.
Hi, and welcome to the Community! 
If I got it right, your Navigator looks something like this:
This happens when you’ve got a mix of normal and numbered chapters.
Is your aim to have a mix of numbered chapters, and normal chapters in your book?
A quick fix for this, is to go to the numbered chapters (eg. “Chapter 1 The Third Chapter), and change them to regular chapters. Here’s how:
- Click on a numbered chapter in the Navigator
- Select the “Style” in the top-left of the toolbar, and select “chapter”
→ The chapter changes to a non-numbered chapter, and the “Chapter 1” part of it disappears.
This way, the chapters are all equal in the book’s Table of Contents, and the Navigator should look normal again.
Here’s a quick video:
Video
Let me know how it goes! 