Hello Karen,
The best way to begin to learn the CODM is to use the example files included with Hauptwerk, then slowly change one setting at a time so you can learn how it works and what it does. The first step would be to copy an example file (by default located in C:\Hauptwerk\HauptwerkUserData\CustomOrganDefinitions) then paste it with a new name. Then begin by editing the file in a text or XML editor changing one rank to point to another organ rank from a different sample set and adjusting the settings appropriate for that rank and file paths.
Be sure to review the CODM user guide which explains all of the settings which are required:
www.hauptwerk.com/documentation
or by clicking in Hauptwerk the Help menu then choosing the CODM user guide in the listing there.