Note that the binary data files created by the Channel Archiver can become hard to maintain as their number grows. For newer EPICS-related archive solutions, consider the RDB-based archiver included in CS-Studio or the EPICS Archiver Appliance.
The manual can be found in manual/manual.pdf
Many of the sources include comments for doxygen. After running doxygen with the file ChannelArchiver.doxy, you should have an API doc. in doxy/html/index.html.