There is a comprehensive Developer Manual for the Naked Objects Framework, download it as a .docx from here: https://github.com/NakedObjectsGroup/NakedObjectsFramework/blob/6aadec10146d007067baeeeb302fb135c869d3b8/Documentation/DeveloperManual.docx?raw=true
At the start of the manual, under 'Writing your first Naked Objects application' is a very simple worked example.
For help, and to view future development plans, please visit the Naked Objects Forum: http://nakedobjectsforum.azurewebsites.net/