To split topics in an HTML file

Open an HTML file.
Position your cursor anywhere between the <BODY> start and end tags of the file, at the location where you want to create the new topic.
On the Edit menu, click Split File.
In the New HTML file name box, type a name for the new file.
In the New title box, type a title for the new file.

Notes

HTML Help Workshop splits the file during the compilation process. The basic <BODY>, <HTML>, and <DOCTYPE> tags will be added after each split. The <TITLE> tag will also be duplicated if you do not specify a new title for each file.
You can have multiple instances of the HTML Help ActiveX control in a single HTML file to split the file in multiple locations.
This feature can be used only with a compiled help (.chm) file.
The split HTML files do not appear in the [FILES] section of the project (.hhp) file. To create links to these files in any HTML file or in your table of contents, refer to the file names specified in Split File. These HTML files are accessible only from the master HTML file until after compilation.