To do this, I first created a cube in Blender with the exact dimensions that I had previously measured. Then I inserted a loop cut to create two compartments. I then applied inset face and then extrude region to each top face to create an empty area to store things. I then dragged the edges downwards to create a sloping side surface. And finally, I used the modifier add bevel (under generate) to create rounded edges.

I used a coarse setting for the slicing (0.4mm) to speed up the printing. For the infill, 10% is sufficient without any problems. The temperature and the build plate temperature were adjusted to the filament, in my case black PLA+.

I was very positively surprised by my first 3D print result. It is already fulfilling its purpose. More boxes will be printed in the future as well…