probably u must have figured it by now,

but still here it is: If you right click on any class name or project
name, the plugin gives you options for making different UML diagrams,
like class dependency, class inheretence, class association etc.

And when it creates the initial diagram, you can create or extend the
UML diagram further, by inheretence, dependency, state diagrams,
further u can synchronize it ur code and refactor..

just play with the options, its easy to figure out :-))

good luck