Convert a web project to EJB Project with CDI and JPA

I have a web project that was developed using JSP , Servlets and JDBC. When built it generates a web archive. Now my task is to remove the JDBC , introduce JPA, EJB and CDI which is on process.

After this I want to split the same project into 3 layers, Web layer, JPA layer and EJB layer. I am using Maven.

I would like to know the best approach for this. Thank you.