Right now, our playerJump event has no subscribers, but changing that is simple and very similar to how we assigned method references to delegate types in the last section:
someClass.eventInstance += EventHandler;
Since events are variables that belong to the class they're declared in, and subscribers will be other classes, a reference to the event-containing class is necessary for subscriptions. The += operator is used to assign a method that will fire when an event executes, just like setting up an out-of-office email. Like assigning delegates, the method signature of the event handler method must match the event's type. In our previous syntax example, that means EventHandler needs to be the following:
public void EventHandler(int param1, string param2) {}
In cases where you need to unsubscribe from an event, you simply do the reverse of the assignment by using the -= operator:
someClass.eventInstance -= EventHandler;