1)Choose a link location in the Design Editor.
3)Highlight the text and click the Insert Hyperlink button .
4)Click the triangle button next to Link To and then select File.
5)Browse to a file, open it, and copy it into the project folder.
6)Generate the file to test links to external topics.
The external file must be distributed in the WebHelp folder.
Microsoft HTML Help projects
The external file must be distributed with the CHM file.
note: The external CHM file must be in the same folder as the project CHM file.