C# decompile

I want to decompile a C# 2010 web form application. I am not certain what files I would use to decompile and where those files are located at. When I  create a deployment project using the setup and deployment method that visual studio will not be using starting in visual studio 2012, I am looking in the bin directory. I would think there would be an exe that i could decompile. However there several dll files.
  Thus to decompile a C# 2010 web form application would i find an exe and/or would I need to use all the dll files? If I use all the DLL files, how would I combine them together so I can decompile?