Before & After Alerts

I drive my child to school, so I'd like create a single event where I set an alert for 1 hour before driving him to school (this usually wakes me up) and then an alert after the event to pick him up. I'm putting in the school schedule for the upcoming year now.

So, the question: is the alert that I set for after the event going to use the start time or the finish time of the event as its basis?

Thanks for your consideration.

Linda😊