This is too much to explain. I suggest that the landlord can read clausewitz's On War if he is interested. There are chapters on the marching and camping of the army in detail. I don't need to say more about the influence of On War, and the professionalism of the Prussian army, the predecessor of Germany, is beyond doubt in European and American armies, so after reading this, I will have a general understanding of the construction of the camp.