How they build their camp?
The army surveyors travelled ahead of the army to find the site best suited for the night's camp.
Once the army arrived, the standards were driven into the ground. Then the contruction of the camp began, every soldier had an assigned role to play. A hole was dug, the earth was used to make a rampart behind it on which the stakes were used to form a palisade.
Here is the plan of a roman camp: