This is a task that you can easily solve with the standard process 'Program Start' event.
Choose the 'FilePickupStartEventBean' in the PI 'Start' tab and configure the path to monitor for new files in the editor 'Editor' tab. You can also define which process attributes should contain the PDF.
With this start event a process will run whenever a file was found in the configured folder and you have access to it on the process data.
![alt text][1]
![alt text][2]
[1]: http://answers.axonivy.com/upfiles/filePickupStartEvent_ea0SmMC.png
[2]: http://answers.axonivy.com/upfiles/filePickup_editor.png
