1. Start by creating your module Help projects as you normally would.
2. Set the BinaryTOC and the BinaryIndex properties of the module Help projects to False and build the HTML Help targets.
3. Create a separate project to use as the hub Help project.
4. Highlight the Project Settings item in the left hand pane of the project editor.
5. Set the ModularHub property to True.
6. Open the hub project document and create placeholder topics for the each of the module Help files you wish to associate with the hub.
The placeholder topic text is generally formatted as Heading 1 topics, but you can use other heading levels as desired.
7. Click the Make Target button to build the hub HTML Help file.
8. In the hub project, choose the Help Target item from the left pane and the HTML Help target from the right pane of the project editor.
9. Set the BinaryTOC property to False and the BinaryIndex property to True.
10. Click the project editor Topics Icon.
11. Highlight one of the placeholder topics and enter the corresponding module Help file chm to the right of the MergeFile property. Enter the corresponding module Help file hhc to the right of the MergeContents property. (The hhc file name is normally the same as the chm file name.)
12. Build the hub project again.
13. Copy the module Help files (.chm) into the hub Help file output directory.
Note that you do not have to copy the .hhc files into the hub Help file output directory.
14. Click the hub Help file View Target button. The contents pane includes all the hub Help files. Click the Index tab; notice that the index list has been merged to include index keywords from all the module Help files.
Note: A full rebuild (Rebuild Target command) overwrites all existing files in the Help file output directory. If you do a full rebuild, be sure to copy the module Help files back into the hub output directory.
More:
Modifying the Context IDs in your
Modular Projects