This page gives an overview of debugging a project in Eclipse and Aptana.
Introduction
Unless you are using a third party debugging tool, you will most likely do your debugging in Eclipse or Aptana via the Debug Perspective. The Debug Perspective is a perspective that is separate from the development perspective that you will likely use for most of your programming work.
The Debug Perspective contains an additional set of views with debugging tools, such as watching expressions, setting breakpoints, and additional console functionality.