Add your own event

hat should I do if I want to add my own events to Gd (not extensions)

Extensions/Functions are made for that, so please explain why they are not suited in your case.

I want them to be like the original GD event,of course, it’s just an idea

Well, I guess you would need to work on the source code of GDevelop and compile GDevelop yourself.

I don’t know how to modify it. Can you give me some advice

It’s quite complex, I’m afraid.
See here for details: GDevelop/ at master · 4ian/GDevelop · GitHub