Thank you Paresh, after spent couple days to learn, I start to understand the design thinking now. The backend is always backend, which means no frontend user(from portal registration) is allowed to access, the way to share information between frontend and backend is we must develop ourself frontend page(form) for portal user to submit data, so that the backend user will receive and process the data, instead of frontend user directly reuse backend form. So, now the question is I'm hoping there would be some tutorial or example for how to develop frontend page, the official tutorial is too simple, I might need a more complicate one.

Jeff

The tutorial touches upon the core concepts and is a good starting point. If you need something more, there are books on Odoo that have been written by various authors. A quick book search on "Odoo" should bring up a long list of such books.