Hi,
I think you are asking about how to import projects into eclipse. The sample projects have to be imported manually by you.
For e.g., if you want to import the sample project that came up with JBPM5.2 you follow these steps :
File -> Import -> General -> Existing Projects into Workspace -> Browse and select Sample ( for Root Directory ) -> Finish
You can see the evaluation project in the "Project Explorer" panel in Eclipse
There are also other example projects that come with each JBPM project which can be imported into eclipse in a similar way.
Hope I have understand your issue correctly. If not please reply back and I will guide you if I know the answer.