Yes second step is copy of the sample FM to your namespace, add your code.
But first step is read the documentation thru transaction FIBF or directly thru transactionBERE
NB: Note that the FM will be triggered just after some CALL FUNCTION IN UPDATE TASK statements, so you could use a CALL FUNCTION IN BACKGROUND TASK to be executed in another LUW after Update Task success. You must not break the COMMIT WORK process here.
Then creation and activation thru FIBF menu of a Product of a Customer and then of a P/S module of a Customer.
Regards,
Raymond