Hi roxy1987,
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:
https://github.com/Salaboy/Drools_jBPM5-Training-Examples
Under the jBPM5 directory you will find a lot of examples. If you want more advanced and feature specific examples you can go here:
https://github.com/esteban-aliverti/JBPM-Samples
Cheers