First decide whether you want to create your processes in Eclipse or using the web tooling. Eclipse contains a wizard to create a new jBPM project, then open the process and start updating it based on what you want to do. Similarly, when using the workbench, create a new project and a new process inside that, which should open Designer. I would recommend starting with a very simply process (for example a hello world script task) and trying to execute that. Once that works, add a new node (for example a user task, or a web service call, or timer node, or ... depending on what you want to model), figure out how to use it and try to execute it.
Thank you Kris. Initially I did not know the existence of JBOSS BPM Suite. After more search, I downloaded the BPM suite yesterday and was able to build and deploy the Hello World example by following the Getting Started Guide. That helped. Are there more examples like that for version 6.0 on the web somewhere? Another question I have is, do I really need Eclipse? I prefer web tool. Since I have no prior experience with JBPM, I was little confused by Eclipse, workbench and so many options. For now I just wanted to start JBPM workflow and call some system commands on a Linux machine that calls an executable to do some work. Thanks for answering my question.