There are two files available in this model for the base. One has airflow gaps on the sides and under which will require supports; the other is a solid box and requires no supports. I just didn't like how the solid box sat on my hard surfaces but that doesn't mean someone else won't mind.
No supports are required for the lid, you should be good. I did put in two files for the lid, one is just the stl, the other is the 3mf with the text already sized and aligned in the event that is easier for some people.
Remember, you'll need to insert a color change for the text (unless you're text will be the same color as the lid).
The author remixed this model.
100 balls was WAY more than I needed so I looked at the STL and recreated as best I could to accommodate 49 (to maintain the x^2 layout). When I remade the lid, I left a 1mm gap between lid and top of box so I could add text in PrusaSlicer for a name.