If test in a behaviour tree?

So I used the Advanced AI tutorial on YouTube by Unreal Engine to create an AI that will run and hide out of the sight of the player, but I want to add in a feature where it only runs when it’s health drops below a certain amount. I can’t work out how to test the health variable (which is global) in the behaviour tree. If anyone could direct me to some beginner level guides on behaviour trees or something because I’m so lost, as they just race through it on the video without explaining what each thing does

The simplest way to check ur health value is to define a decorator …
Do it like this:
link picture

  • Define a new Decorator.
  • Get two editable values: UrHealthValuefrom the blackboard(BlackboardKeySelector) + TheValue u want it to compar(float)
  • Override Perform Condition Check

If ur check is the tree goes on if not he will stop at that point

How did you get “Perform Condition Check” and “Return Node”? When I create a new decorator it’s empty

Go to the left side of the screen…
Hover ur mouse above the “+”, next to “Functions”
click on override - a dropdown menu should appear and now you just pick Perform Condition Chek