Hi Manuela,
Business role is just container in which roles from different systems can be grouped in to one business role and these roles just exist in GRC system only.
Role generation is for the roles which need to be generated in backend systems.
Basically you need to define a process in your project with respect to creation/maintenance of business roles and how to mitigate the risks in case of risk violations with business roles.
In our environment all business roles creation/maintenance is done by GRC support team and its their responsibility to make sure all business roles are risk free and in case of violations need to discuss with Role owners and should amend the changes accordingly.
Let me know if you have any queries.
Regards,
Madhu.