How do I add an automatic pause (and a play button) after each video segment.
You could do that on a DVD-Video, or BD, though that Pause would be a return to a Menu.
In a full-featured authoring program, you could create a Menu that was either blank, or maybe had the word Paused on it. It could be timed to show for a pre-determined period, then auto launch to whatever its End Action was set to, or to activate with certain Buttons, depending on what one would want. PrE does not offer that sort of control.
If you are looking for a way to output an AV file, then have it Pause and Play, I think that you will need to do that with the chosen player's controls.