The text and other content in your projects is organized in "topics". Each topic is stored in a separate file in the Project Files section in the Project Explorer.
Creating a new topic in the TOC creates a TOC entry and an associated topic file in the Project Files section. Creating a topic in the Project Files section creates a topic file without a TOC entry.
A topic is like a word processing file; it is a document dealing with one subject and it is generally represented by one entry in your Table of Contents (TOC).
Each topic is stored in a separate file stored inside your project. The entries in the TOC are actually separate from your topic files. The TOC entry is really just a link pointing to a topic file.
Creating topics in the TOC:
When you create a topic in the TOC you automatically create a TOC entry and a topic file in the Topic Files section of the Project Explorer. When you click on the TOC entry the topic file is displayed for editing automatically.
Creating topics in the Topic Files section:
If you create a topic in the Topic Files section of your project it will not have a TOC entry. Topics without TOC entries are used for popup topics, topics displayed only by hyperlinks and topics used as snippets (reusable content that you insert in other topics). They are not exported to PDF, ePUB or DOCX output files.
How topics are managed in your projects:
Although your topics are all separate files Help+Manual manages your project as though it was one big file for some functions. For example, you can perform global search and replace operations on all the topics in your project and your formatting styles also apply to all your topics.
The Table of Contents (TOC) in the Project Explorer is a representation of the structure of the TOC in your finished documentation. The TOC is used to organize your project into chapters and sub-chapters. In the Project Explorer it works like an outliner, allowing you to move topics and chapters around and change your structure quickly and easily.
Topics included in the TOC are listed both in the Table of Contents section and in the Project Files section of the Project Explorer. The Project Files section shows all the files in your project, the TOC only shows those files that will actually appear in the table of contents of your documentation. It's important to understand that the topics in the Topic Files section are not duplicates – you are viewing the same topic files in both sections.
See Managing Topic Files and the TOC for information on working with topic files in the Project Explorer.