After fridge, proof the dough for one hour the next day, which day is the next day?

That's what I thought, but is the proof of just one hour after shaping long enough?

I believe the "next day" remark is meant to orient you to the fact you are doing the proofing on the day after you mixed the dough. The entire recipe is completed over two days' time. Day one you mix, warm ferment, stretch and fold the dough. Then it does a cold bulk ferment/rest in the refrigerator overnight. The next morning/day, you cut, shape, proof and bake.

This recipe is made over the course of two days. It's mixed and bulk fermented day one, then into the fridge overnight until day two. On day two, pull the dough out of the fridge, divide, proof, and bake.