We are working at a more polished manual and user guide. An incomplete version is available and is updated as we proceed. If you use Kappa, please cite this one.
An older reference manual is available as an online html version. Manuals that are less tightly curated are available in pdf with the stable releases. Consider the new version (above) even as it is catching up with all the material.
Jean Krivine's teaching page provides some material to get started with KaSim.