Random Cooldown Behavior Tree Decorator

I am trying to create a new behavior tree decorator in blueprint which is identical to the built in ‘cooldown’ decorator, except it will wait a random amount of time. I overrode Perform Condition Check

but I cant figure out how I am supposed to actually work this. Should I be using a timer? a delay? and where should I be starting the timer or delaying? The idea was that after the delay/timer completed, IsComplete is set to true.