SAP PI7.3 and NW BPM tutorial

Hi

can you point me to any BPM tutorials that explain a simple scenario that uses SAP PI7.3 interfaces that are integrated into a NW BPM.

I have followed the tutorial from NWDS help page on process demo scenario describing ordering a book, Steffen Ulmer's My Name & Age Tutorial.  But these do not explain how to link up interfaces.

(I was not able to find the PO modelling process tutorial that the NWDS welcome/help page mentions - that one seems ideal if I could find it).

thanks