The tutorials which would probably help you would mainly be based around the C++ language itself. GDK is a wrapper for the DirectX library which makes using the DirectX stuff so much easier.
Searching around google you will end up finding millions of C++ help and documentation. I always have google open when I'm deep into my programming projects. Sometimes MSDN, sometimes other websites.
Dark GDK does start your project different from other C++ projects as your code will have to start within the void DarkGDK ( void ) function. Everything else from then on carries on as if you were running from main() or something.
Apart from that, as you progress with your own projects the TGC forums are and excellent source of help where required.
Warning! May contain Nuts!