The following commands create a copy of the help on help volume and make its files writable. (Presumably the projects subdirectory already exists.)
cp -r /usr/dt/dthelp/help4help/C /users/dex/projects/NewHelp4Help chmod -R u+w /users/dex/projects/NewHelp4Help
To build a new version of the run-time help files, first ensure that the directory /usr/dt/bin is in your search path. Then, change to the new directory, rename the Help4Help.htg file, and run HelpTag:
cd /users/dex/projects/NewHelp4Help mv Help4Help.htg NewH4H.htg dthelptag NewH4H
When the HelpTag software is done, you can display the new help on help volume using this command:
dthelpview -helpVolume NewH4H