No. No, no, no.
You say you know Java. I don't think you do.
We tell you to call the getRegistry method on an instance of RegisterEvent.Register. So you need to look around and see if there's an instance which you can use. Hint: it's the single parameter in the method. Then you need to call the getRegistry method on that specific instance. And apparently, that's too hard for you.
You have a perfectly fine, working method commented out at the bottom of your Main class. Uncomment that and put it in a class annotated by @Mod.EventBusSubscriber.