Well, this is the wrong forum, but I see that you have posted the same question under the article.
MFC (and C++ for that matter) is a different animal compared to C# or VB.NET.
The code for a dialog (form) is usually located in four files. For example:
MyDialog.h MyDialog.cpp resource.h MyProject.rc
Both the last files are usually common for the whole project.
So if we take a look at this specific project we find these files:
MainFrm.h MainFrm.cpp
resource.h
HexEdit.rc
In a solution explorer you have to add the tab Resources and look for dialog in order to see the visual form.
Now the only problem is to learn C++ and MFC in order to translate the code into another language.