Flip the model in your slicer to the other side.
Layout
http://www.keyboard-layout-editor.com/#/gists/b696cb87b4e10608d2374c7b42fde7b5
Firmware
https://github.com/mvaneijgen/mvaneijgen_split_keyboard
Some keycaps are 3D printed using the SCAD keycap_playground by @riskable https://github.com/riskable/keycap_playground
The author marked this model as their own original creation.