There's a video tutorial on it here:
I don't know how good the tutorial is, but I recomend against using the Debugger because it is problematic. It's slow and crashes often. That said. It's not a bad idea to understand how to set break points and step through code.
Debugging is something of an art form. The tools are only there to help you investigate the code. They don't do the work for you. In order to do debug you have to learn how to think critically about the code you are investigating.
Thom Parker - Software Developer at PDFScripting