Combine the active starter and warm water together until it's milky ish, then add the bread flour and the salt. Mix with a dough whisk or wooden spoon (or stand mixer) switch to your hands if needed until you get a shaggy dough. cover and let it sit on the counter for one hour on the counter.
After one hour, start the stretch and folds. Act like there's four sides to the dough. left one side, stretch it up and slap it down to the opposite side. repeat on all four side sides. Cover and let it sit for 30 minutes do another round of stretch and folds and repeat until you have done a total of 4 rounds.
After the last stretch and fold, Cover it again and leave it on the counter for 6-8 hours or until the dough has almost doubled in size. This process can vary depending on your climate and the temperature that day. Hotter days will ferment the dough faster and colder days will be slower. Keep an eye on it so it doesn't over proof.
Once the dough has proofed, Flip the dough onto a lightly flowered surface. carefully stretch it out and start the folds. Trifold it by folding one side to the center, and then the other side to the center slightly over the first side. Then start rolling it away from you. Now create tension in the dough by pushing it away from you then pulling it towards you, creating tension on the counter and tucking underneath the dough and continue just a few times until you have a nice round dough.
Flip it into a floured Benetton (or you can use a colander with a tea towel in it) Flour the top, cover and let it sit on the counter for one hour and then stick it in the fridge overnight or up to three days. The longer you let it sit in the fridge for cold fermentation, the more sour it will be.
When you're ready to bake, preheat your Dutch oven in the oven at 450° for 30 minutes. Turn your dough onto parchment paper or a silicone bread sling. Flour at the top and score it however you'd like.
Place inside Dutch oven and add a few ice cubes. This helps create steam to make that classic crispy crust. Place the lid on and bake for 30 minutes. After 30 minutes take the lid off and bake for another 15 minutes. Let it cool on a cooling rack for at least 1-2 hours before cutting into it. Enjoy!