Platform Settings General Tab

Exclude feature from build (Visible if a single feature is selected)
Check to exclude the selected feature from the build. This check box is only available if you have selected an individual feature.
Release Directory (Visible if the Platform is selected)
Enter the location of %_FLATRELEASEDIR%, which is where the Make Image Binary Tool (Makeimg.exe) looks for files when it makes the new operating system image. Use the Browse button to navigate to the location.
Build Type (Visible if the Platform is selected)
Select either Debug or Retail. A debug build contains full symbolic debugging information and is without optimization. A release build, also known as a release configuration, is optimized for maximum speed, and therefore is built without full symbolic debugging information. By default, a Debug build enables debugging and Release configuration disables debugging but users may use the Enable Kernel Debugging check box to override the defaults.

Additional resources