c# shell extension

I currently have a 32bit shell extension written in delphi. I need to extend this functionality to 64 bit using c#. The shell extension shows in the context menu of windows explorer. In short, when the user right clicks on a file, the context menu shows, when the context menu is clicked, it shells a specific application with a list of the file or files selected from the context menu. I need to replicate this functionality with a c# shell extension.