How to wire up a project loaded eventListener in a UXP Plugin?

How to add an event listener for Project Load using Premeire Pro UXP API? In the docs there is an EventManager class ( has an addEventListener function), there is ProjectEvent (EVENT_OPENED, EVENT_ACTIVATED, EVENT_DIRTY).  Not sure where and how to wire up this event listener. There dont seem to be any examples in the documentation on how to do this.