[The following useful is old. I haven't been able to update it. It may or may not work. And read all comments below before executing commands.]
Here is a photo of the default layout: https://github.com/c4software/xd75re/blob/master/layout/default/default_layout_all_layer.jpg
Create you keyboard layout here: https://config.qmk.fm/#/xd75/LAYOUT_ortho_5x15 Click "Load Default" to bring up the default layout. Edit it or use your own layout. Download the layout to a file because you will want to edit it later again. The layout