Start by downloading the XBMC nfo info provider here : http://forums.plexapp.com/index.php/topic/16293-nfo-agent/
Open the bundle using "Show Package Contents", and then navigate to Contents ->Code-> _init_.py. Open that with a text editor or code editor of your choice. Get a feel for it and post back when you are done.
Let’s go ahead and work with that movie then. Make a new folder and copy (don’t just move it, make a copy) into that folder. Then make a new section in Plex Media Manager with this folder.