The documentation for Wicket Objects currently consists of a user guide intended for programmers looking to use the project as a Wicket-based UI for a Naked Objects domain model.
The user guide also has an application walkthrough so that you can quickly assess whether Wicket Objects is a good match for your requirements.
Wicket Objects runs on top of Naked Objects, which means following the Naked Objects coding conventions when writing your pojo domain objects. There's more information on the Naked Objects website.
You might want to check out the book Domain Driven Design using Naked Objects, which provides a tutorial on writing domain apps using NO.