Hello Laura;
Probably you are looking for a White Paper to get based and create your BBP document.
I recommend you to see the blog --> http://scn.sap.com/community/plm/rpm-collaborative-project-management-and-cfolders/blog/2013/03/22/how-to-set-sap-ppm-objects-with-business-requirements
I recommend you to get the PPM Configuration Content documentation from SAP Service Market Place and get all of the important point of that document and get focus with this to your key users.
Let me know if you can access to those documents.
Best regards,
Mariano