Subscribe to the Chandra Users' Discussion Group . CIAO 2 Documents CIAO offers several ways to learn about the system. The most straight forward is probably to follow one of the science data analysis threads that lead you through the most common types of Chandra data analysis, whether imaging or grating spectroscopy. Some of the analysis described in threads have been automated into unix scripts . These scripts are available from the download page.
Some applications are more complex than a few simple threads can do justice to.
For these we have written manuals . Sherpa in particular is a very powerful and flexible modelling and fitting engine. You may also find the CAL page useful. For help on a particular tool use the ahelp system. You are probably not the first person to find some aspect of CIAO confusing at first.