changed:
-
For the time being, you have to look at the code. 

It is fairly well documented and straight forward (if you know C++ and OOP).

Start with an object which is similar to what you want and derive a new class. 

The biggest issue right now is how to load in GEM as a DSO/DLL. 
For SGIs, you will need to setenv LD_LIBRARY_PATH. 
On NT, you will need to have your path include the directory with GEM.