The easiest way to do that, would be to simply drag and drop the UI Text gameobject or component into the FlowCanvas Editor.
This will popup a menu, in which you can choose what you want to do with the object dragged 🙂
In your case, you will need to select “Text/Properties/Set_Text(string)”.
This will create a node for you in the flowscript, which when executed, it will set the UI Text to a new “Value”
Gavalakis
