Narrat mobile support
Narrat works on mobile by switching the layout to a portrait layout where the viewport appears on top of the screen, and the dialogue window takes the rest of the screen.
Hose to use Narrat for a mobile game
Narrat games should work on mobile web out of the box, you can try opening the url of your narrat game on your phone.
How to export a Narrat game as a mobile app
Turning a narrat game into a mobile app is more complicated and hasn't been tried yet, but might be possible with tools like Cordova. You'll have to experiment with it.