Visual studio 2012 C# connection with AutoCAD 2009

Question

Hello 

 I am very new to C# and could you please advise/ guid me the inital settings of C# for accessing Autocad features.

I would like to draw a simple figure like stepped rectangle in AutoCAD work space by running a C# script. I am using 

visual studio 2012 and C# and AutoCAD2009. 

thanking you in Advance

Anil