Creation of a very simple change to a program

Hi I would need a new community builder trigger (will be provided to you) to be implemented in two points (which will also be provided to you). What needs to happen is that the Community Builder trigger only gets triggered when a person has registered for an event. In short here are the working instructions explaining exactly what I want: [login to view URL] Here are the instructions of where to put the triggers: [login to view URL] Please note that the process will need some variables to be sent through the triggers. Expected work time: about 1-2 hours. Optimal: 10 minutes.