With slightly wet fingers, scrap a piece of the dough away from the bowl. Grab a section of the dough and stretch the bread dough above your bowl. Then fold over on top of the dough.
Rotate your bowl clockwise a quarter of the way and repeat identical stretch and fold. Repeat the process until you come full circle, about 4-6 times. You will notice the dough will start to look much smoother than before.
Cover the dough again and let it rest for another 30 minutes.
Before the next set of S&F, prepare the mix-ins. Bring a small skillet to medium-low heat, then toast the walnut for about 5 minutes or until fragrant, stirring often. Be sure to keep and eye on the walnuts! They burn easily. Remove the walnuts from the heat and allow them to come to room temperature. Give them a rough chop. Set aside.
Pour the chopped walnuts and ground cinnamon on top of the dough, then perform the 2nd round of S&F. Cover the dough and let it rest for 30 more minutes.
You can add the mix-ins during any of the rounds of S&F, however, I prefer to add them during the 2nd round so that the mix-ins can continue to be incorporated during the following sets of S&F.
Repeat the same stretch and folds for a total of 4 rounds with at least 30 minutes of rest in between each set. Cover the dough after each round of stretch and folds.
Once you have completed the final set of stretch and folds, cover the dough and let it rest for the remainder of the bulk fermentation on your counter, about 7-9 more hours if the dough is kept at 70 degrees F.