I need some help with events

how do I make an “on create object” or “on delete object” event in my game?

When you use the “Create an object” action, all actions in the same event box targeting that object will target the object you just created. The only exception to this is if your conditions (or prior actions) include checking/picking multiple objects.

As far as I know, there is no “on delete object” equivalent, you would just need to put your actions in the same event box that you delete the object.

You can also build out your own custom behaviors that allow you to do something similar, although it can be more complex depending on what you are attempting. Custom behaviors: create your own behaviors with events [GDevelop wiki]