Understanding context-sensitive help in C#.Net software using MAP files and RoboHelp9 project

we are trying to enable context-sensitive  (F1) in our help content.  I found some reference to MAP files in the RoboHelp manuals/help but it's rather sparse for context-sensitive noobies.  Does anyone have experience doing this and what good resources are?  We are trying to context-sensitize a C#.net application on Visual studio 2008, if that helps