Scoring gives your dough space to expand without splitting.
Score just before you transfer your dough to the pot for baking. Dusting the top of the dough lightly with flour will keep the blade from catching. Try to score quickly and decisively. Keep the blade at a slight angle to the dough to get a coveted ear (the crunchy piece of bread that lifts off from the scoring) and aim to score about 14 ⁄ inch (5 mm) deep. The design is up to you!