From within 'Property Hive > Settings > Digital Displays' you can choose the layout you wish to use:
The add on comes with 2 layouts out of the box with the added option to create your own custom layout.
Simply select 'Custom' from the layout options and create a file called digital-display.php in the location that it specifies.
If you're looking to base it off one of the existing two layouts these can be found in /wp-content/plugins/propertyhive-digital-window-displays/includes/layouts/.