Stretching and folding means picking up one side of the dough and pulling it upwards and then folding it over the dough. Do this 3-4 times all around the dough ball. This tightens the dough and helps trap air bubbles helping with gluten development too.
After stretching and folding cover it so it doesn't lose moisture and let it sit at room temperature for 30 minutes to rise. Do this step 2-3 times with the final stretching and folding done in your baking vessel lined with oiled parchment paper.
