A help topic is a unit of information identified with a unique ID. Help topics are grouped into a logical framework that best describes the product you are writing online help for.
Each topic you write should have an element (or tag) that marks the start of the topic:
<element id=id> Help Topic's Title The body of the topic
Where element is one of the following: chapter, s1, s2, ..., s9. The body of the topic may begin on any line after the title.
The topic's position within the topic hierarchy is determined by the element used to start the topic and by the element used to start the immediately preceding topic. For example, a topic that starts with <s2> and immediately follows a topic that starts with <s1> makes the <s2> topic a subtopic of the <s1> topic.
The id is required if the topic is to be accessed either from the application (if you are writing application help) or from a hyperlink.
The help topic title can be any string. If the title string occupies more than one line in your source file, end all but the last line with an & (ampersand). To force a line break at a particular place within the title, use a \ (backslash) character.
The following line marks the start of a topic using the <s1> tag:
<s1 id=welcome>Welcome to My Application
To force the title to be displayed on two lines, you use a \(backslash) like this:
<s1 id=welcome> Welcome to \ My Application
Chapter 2, Organizing and Writing a Help Volume, describes the general structure of a help volume, including how to create a topic hierarchy.