Being able to debug Sitecore code is an important skill for supporting Sitecore solutions. There have been a number of excellent articles on how to do this, but they typically describe using JetBrains DotPeek product as a "symbol server". (See http://bilyukov.com/debugging-sitecore-dotpeek/, and https://jammykam.wordpress.com/2015/01/11/how-to-debug-sitecore-kernel-in-visual/). An alternative, which I find somewhat simpler, is to use ReSharper to generate PDB files, and place those in your solution bin directory. I will walk you through that approach in this article.