The dough bubbles and more than doubles in volume in the bowl when the yeast is slowly working. If you wait too little, it hasn't risen yet. If you wait too long, it will rise and then start to flatten back. You can see this from the sides of the bowl, that the dough has reached a higher level earlier, and started to contract, but left some marks up to the maximum where it was. I guess the timing depends on how much yeast you added exactly, and the temperature in your kitchen. You don't need to get it perfectly right, but it you wait way too little or way too long I guess the bread comes out dense.
You just scrape the risen dough from the bowl into the dutch oven with minimal disturbance, so you don't disturb the air bubbles too much. And your oven and the dutch oven need to be hot at this point, so the dough goes right into a hot oven, the heat expands the air bubbles and gives you some oven spring.
Other recipes make you sprinkle flour on a working surface, fold and shape the dough into a loaf, and then leave it, giving the shaped loaf a second rise.
You just scrape the risen dough from the bowl into the dutch oven with minimal disturbance, so you don't disturb the air bubbles too much. And your oven and the dutch oven need to be hot at this point, so the dough goes right into a hot oven, the heat expands the air bubbles and gives you some oven spring.
Other recipes make you sprinkle flour on a working surface, fold and shape the dough into a loaf, and then leave it, giving the shaped loaf a second rise.