C# 2010 web form app

Question

I have a C#. net 2010  web form application that I am going to maintenance and add linq to sql statements in the existing application. This application communicates with a sql server 2008 r2 professional edition database.

My problem is acutally wanting to know who to debug (step through) the code.  I can get the general idea of what the code does. Howeever, I would like to know how to step through the code. Can you give me some help in this area?