i tried yesterday - and here is what i can say :
It's a normal Win32 DevCpp installation.
But there are some so called "DevPacks" for AmigaOS4, AmigaOS3, Aros, MUI, Feelin, ...
GCC Compilers for all amigas are included and all the amiga os includes stuff are also included.
So that, you can compile project for Win32 or AmigaOS from windows.
Since the executable is compiled, start your WinUAE to test your program.