Proper FactGroup implementation?

Hello, I am trying to implement a custom fact group and just want to make sure I’m doing it the right way. I understand that you are supposed to override the factGroups function in FirmwarePlugin, but I’m not exactly sure how to do this, or what the purpose of this function is. Is it just supposed to be a modular function so that you don’t have to hard-code in the FactGroup and FactGroupName declarations/initializiations in vehicle.cc/vehicle.h? If so, what would one actually put inside the factGroups function?

Thanks in advance.