Auto-Parser: how to make it work?

I know next to nothing about Applescripts but managed to easily install a couple of scripts to OmniFocus 2 on the Mac. However, Joe Buhlig’s Auto-Parser, which seems like to could be a real time-saver, has me flummoxed. I can’t find the pList file and I don’t think I understand what is meant by changing the path in the pList file. Can anyone help me with some additional instructions to allow me to install the Auto-Parser script?