The manual's are compliant with the chapter structure prescribed by EASA and must basically not be altered.
You may add chapters to your existing structure, but we strongly recommend to use this feature with caution. Why?
a. because you can't delete those chapters yourself
b. because the numbering will always be chosen automatically, in order to avoid conflicts with existing master template chapters. Even those you may not see depending on your profile configuration.
c. because you can "Customize" any chapter title and content using the "Customize" button