Steps for preparation

Combine flour, bran, salt, and instant yeast.
Mix it up with a wooden spoon
Let the dough sit at room temperature for 2 hours. Visible foaming will be there, which means the yeast is alive
Cover with a lid and keep in the refrigerator from 24 hours to 48 hours.
Dust your hand with flour and form the dough into a ball. Try to touch your dough as little as possible.
Rest the dough on a parchment paper which has been sprinkled with either cornmeal or flour. Let the dough rest for 45 minutes. No need to cover
Put some slits in it. Flop the whole thing in a preheated hot oven. The oven temperature should be about 450˚F
Cover with the lid and let it bake