Let the dough ferment at room temperature for 4-6 hours. During this time, it will puff up nicely but will not quite double.
At this point, you can go ahead and divide and roll out the tortillas, or place the dough in the refrigerator for at least 4 hours or up to 3 days.
Rolling Out Sourdough Discard Tortillas
Divide the tortilla dough into 12 even pieces. (If your dough has been in the fridge you can use it right away. There's no need to let it come to room temperature.) With your hand cupped, gently roll the dough on the counter to form a ball.
Let the dough rest for about 15 minutes and then start rolling out your tortillas. Dust the work surface with flour and use a rolling pin to roll the dough into a flat circle about 8-10 inches wide. Turn the tortillas periodically as you roll them out to keep them from sticking to the counter.