Steps

1. Pick up the timer activity from the palette as shown below.
2. Open the Timer Activity Properties and assign the Interval Value like in my case I want to the timer to trigger every 10 secs. so I have put 10s as Timer Cycle.
3. Placed a Scripting Task after the timer to valid the flow triggers.
4. Build and Deploy.
5. Check in the console "Timer Triggered"

Process Flow Diagram

Process Flow

Properties

You can see the console and you will see after each 10secs you will get the timer triggered.

More Readings : Timers JBPM Documentations

Thanks

Sanjay Gautam