The entire procurement to payment process is described in detail in the following manuals:
Introduction to Procurement & Suppliers
There are quick guides illustrating the process for requesting a new supplier found on the FMS Training Pages under the heading Suppliers.
Training Courses
Training courses on Suppliers and Purchases are run periodically. Go to the Course Booking site to put your name on a waiting list of this course.
The instructions that have been issued to Suppliers can be found here.