How to custom the project file structure tree?

I have read the plugin document (IntelliJ Platform SDK/Tutorials/Tree Structure View), but i still do not know how to add some folder or files to project when i create a new project.
I want to create a plugin: it can create a new project type, and when i select it to create new project , it can contain default project structure tree which is custom-made.
Is there anyone can tell me how can i do that?Thanks.