GEF Simple Doubts!

Hi, I am very new to GEF. I am on a mission to make a Graphical Editor. My first step is to make something similar to Shapes Diagram example/ Database Schema Editor. That is, I want to make a plugin which opens and works inside the Eclipse. I don't want to make a standalone application. I have the source code of Database Schema Editor but there is no plugin.xml from which I can learn how to make a plugin. Please help me, guys. It is very urgent. Thanks a lot, Aatish