Painted in PrusaSlicer 2.4.0-beta1; won't work with version 2.3.3 or earlier.
Simply load up each .3mf file as a project into [at least] PrusaSlicer 2.4.0-alpha1 (i did these using beta1) and the painted segments and supports should be on each applicable part. Feel free to move each part around and/or modify any print settings as you'd like - these settings are simply what I used and come as part of the file.
I oriented the long top part vertically so it blends together with the front and back parts better; the supports for the peg holes might not actually be necessary.
Also you may want to size down the long pins to 97-98% to make it easier on your thumbs.
Original model by Martin Taichl.
The author remixed this model.