To create a Diptych
Go to “Print” module under the main menu
Under layout style select Custom Package
Now under Rulers, Grids and Guides , check and uncheck the options as per your requirement like page grid, rulers, image cells, dimensions etc.
After that adjust other settings like file resolution, custom file dimensions, JPEG Quality
Now you can drag and drop the images on your film strip onto the blank page and arrange them
When done, choose print to file to export your diptych