MsBuild is a complex beast. It’s easy to get lost inside the XML and hard to discover what exactly is going on.
One tool I recently discovered is MsBuild Explorer:
Use MSBuild Explorer to help you find your way around the make-up of your build file(s). It presents you with a treeview to see the targets that you have available. A series of tabs provide access to more information including detailed target information, custom target execution, detailed property, item, import and using information and evaluation.