Just the thing if your figures need some cheap shelving for their workshop, garage, or basement. This is the kind of furniture that someone might knock together from some surplus 2x4 boards.
A note on the customizer options- you can choose to generate a preview, which will generate the parts in the orientations they'll need to have once the shelves are assembled. That's meant only for checking your proportions- don't try actually printing that. Instead, choose either the plated option to get all the parts generated as a single file, or generate the sides and shelves separately if you prefer to do the layout yourself.