The panel in the top left of the demo scene will display data from the Blackboard. Notice how the UI Text doesn't update until data is added to the Blackboard. In your project, you may wish to add data at Start() if you want the data displayed before anything has otherwise been sent to the Blackboard.
Check each individual page for the various quests in the demo scene. While I have tried to provide multiple examples of common use cases, there are many, many ways to use the Quest system. Come to the Discord to ask questions and engage in discussion.