First, discard 80% of the starter from yesterday, leaving 1 heaping tablespoon of starter in the jar or bowl. Next, add the flour and begin to drizzle in the water. Keep adding the water and stirring until it has the consistency of thick pancake batter. Mix well and make sure there are no lumps. Cover the starter with a kitchen towel or lid set on top (don't screw on the lid) and let it rest in a warm spot for 24 hours.