Hello,
I'm not sure if you are referring to general events in RTOS or the ones in the Wireless connectivity stack, if you are developing your own application you will be required to define task events and queues for the desired behavior of your application.
To understand more about what is done and set with the different events available in the examples, please check the BLE Application Developer's Guide which it's available in the documentation folder of your downloaded SDK.
Regards,
Estephania