You should take a look at the documentation, because there was a lot of changes between 4 and 5 as you already notice. You need to take a look at the Knowledge APIs and if you want you can also take a look at some examples located here:
Under the jBPM5 directory you will find a lot of examples. If you want more advanced and feature specific examples you can go here:
Thanks for replying Mauricio. These examples look really good. Now At least I know how to start
You are welcome Roxy, can you mark this question as answered so it's easier for the people when they look for an answer?