There is a sample C program and Makefile in example/, which I will try keeping up to date.
Also, the header files are a good source of information on what parameters a function needs.
All the necessary functions to use in your application are in kajamtag.h.

To install:
./autogen.sh
make
make install

This places some header files in /usr/include/kajamtag, and places a shared library in /usr/lib or /usr/lib64 named libkajamtag.so

#include <kajamtag.h>
To link against libkajamtag.so, append -lkajamtag to your gcc compile line.

C++ and Python bindings will be coming eventually.