Debugging Abap webdynpro appln

Hi,

Please tell me how to debug the Webdynpro application.. This is with regard to my ongoing issue which is discussed in my earlier question,

Problem with Dropdown list box data binding

Please help me with understanding the control flow of the webdynpro application, which is the first step while execution, when is supply function called and when are the event handlers called..

Thanks in advance,

Sachidanand.B