Here at least you need to setup the location (aka directory) where the PdfScanManager shall keep an eye on for new PDF documents.
In fact you can set up 2 locations: Inside an arbitrary folder and in your "My Documents"
Keep in mind, how you set the "File-name filter" related to the output of your scanner or fax system.
If you put in here "*.*" it will work in every case, but it will also put every renamed document (that you have already processed) again in the Todo-List, if you did a "Simple rename" or "Rename and mail".