The overall Unison feature set was discussed in the overview for Unison. The detailed implementation for this feature set is best seen in the man pages for Unison in a classic Linux style. The Programmer's and Tutorial Guides provide additional clarification if required.
After you have installed the product, the Quick Start Guide will step you through the demos. The man pages are conveniently located at the top of the Unison source tree or on line here.
The Programmer's Guide for DSPnano is available as an add on to the open source version and is part of the standard release for the commercial version.