Using a whisk combine the water and sourdough starter
Next using a wooden spoon and possibly your hands incorporate the flour
Allow the dough to sit for 20 to 30 minutes
next sprinkle in the salt and add a splash of water to help incorporate the salt use your hand to incorporate the salt, you will notice the doughs texture has changed quite significantly, it will take a couple minutes of massaging and kneading the dough to ensure the salt has been evenly mixed in. After that cover the dough for 30 minutes
After 30 minutes has passed, it is time to do the first stretch and fold. Start on one side of the bowl and grab one edge of the dough and pull it up and then fold it over on top of itself, go around the bowl doing this, it should take at least 4-6 times. Cover and let it rest again for another 20-30 minutes.
Repeat step 5 every 20-30 minutes until you've done it at least 3 but 4 times is even better
After all of the stretch and folds cover the dough for the bulk fermentation. for me this typically takes 8ish hours but that will vary based on temperature, what you will be looking for is for the dough to at least double in size, and be bubbly on top. Once both of those are present perform the window test. Scroll up to the paragraph i wrote on bulk fermentation to a get a better understanding of this!
Once bulk fermentation is complete, dump out your dough onto a lightly floured surface and shape it into a round boulle, start by stretching it out flat then folding each side in toward the center then rolling it up. Then push and pull it against the surface rotating it until you get a nice round shape. Their are also many other ways of shaping bread however this is what I use because it is simple. Let the dough sit on the counter for about 20 minutes.
After 20 minutes you will see that the dough has started to relax, stretch it out again a reshape it.
After the second shaping transfer it to a proofing basket or a bowl lined with a tea towel. I like to place a a piece of plastic wrap loosely overtop before folding the tea towel overtop. Then place it in the fridge to cold proof over night
The next morning preheat the oven to 475 degrees Fahrenheit with the dutch oven inside and remove the bread from the fridge. Transfer the dough to parchment paper. Once the oven is preheated score your bread dough and transfer it to the hot Dutch oven. Under the parchment paper place two ice cubes on either side of the bread. Alternatively you can do a splash of water under the parchment. This creates a crispy bubbly crust.
Bake 25 minutes covered and 10-15 minutes uncovered. Allow it to completely cool before cutting!