Before you build a project you need to configure how to build in a build configuration in the IDE.
The following build configurations are available: Debug build and Release build. You can also create your own custom build configuration.
You use the Configuration Manager to choose the build configuration to use for your project / solution, create new build configurations or edit the existing ones.
The combination of configuration type and platform settings define the build configuration of your project / solution. For example you can create a Debug build configuration for x86 platforms, and a Debug build configuration for x64 platforms. Use the project's properties to view and change the platform type for which you want to build your application.
See the Visual Studio Help for more information on build configuration and build configurations and build platforms.