Well, first of all you'd need at least some knowledge of C++.
After that, try to find the dbpsh.h and globstruct.h files on this forum, and download the latest DirectX SDK.
Afterwards, you create a new project (use DLL option when creating the project) and include
dbpsh.h,
globstruct.h and
d3d9.h. If you're using MSVC++ Express, then you'll have to specify the DirectX SDK include and library folder in the project properties. (
Project >
Properties >
VC++ Directories and then add the directories in
Include Directories and
Library Directories). Those directories can be found where you installed the DirectX SDK and are called
include and
lib.
After that, read DBP's
TECHNICAL DOCUMENTS >
Third Party Commands for the specifics about creating a DLL for DBP. And also read
this to build your stringtables if you're using MSVC++ Express.
I don't think there should be anything else you will need to make your own plugin. Try to keep it simple for starters, it will make it easier to debug.
Cheers!
Sven B