For Marble we need a Map Creation wizard:

1.) On right click on the "Theme" listwidget inside the "Map View" tab on the left a context menu should appear that has the menu entry "Add Map Theme". clicking it should start the wizard

2.) The first page of the wizard queries the "Map Title", the "Map Theme" and a description of the map.

3.) The second page queries the basemap jpg and the Preview Image

Ideally these pages get created as UI-files to allow for better maintainability.

Once the user has entered the queried data the input gets converted into a dgml file and the required directory structure.

As a result the map theme appears in the "Theme" listview.

Documentation:

https://techbase.kde.org/Projects/Marble/CustomMaps