Connect my existing Java project to vaadin framework.

My existing java project, which is a stockreorder database was created using entity manager. how can i put this on the vaadin framework for a web app version. I am new to vaadin, so please explain in steps if you can. Thank you.

Without knowing much of your current implementation nor your technology stack I recommend at least these two resources:

This is a good explanation of transforming a Swing application to a Vaadin application:

Matti and Thomas recently made this webinar where they explain best practices when using JPA with Vaadin.