It's up to you to implement the actual dialogue rendering and input control. There are a few example projects available on my Itch.io page that demonstrate some of what is possible.
There is also an example balloon that is provided by Dialogue Manager to help get you started on building your own.
There is a "Create copy of example dialogue balloon..." item in the Project > Tools menu. When you click it, you will be prompted to choose a directory to save the copied files into. From there, you can edit the new balloon to make it your own.
The most common thing you might want to do is adjust the font and margin sizes. The simplest way to do that is to edit the theme that is attached to the Balloon panel in your new copy of the example balloon.
An example of what's possible in a more complicated balloon is what I have in my own game:
With a bit of extra code, balloons can follow characters.