A Laser is used to establish and check the flatness of the field. In this picture you see a laser, mounted on a tripod which has been very carefully leveled. The laser shines on a spinning mirror. This causes the laser light to go out in all directions in a horizontal plane. This plane can be detected by special photo-sensitive detectors, such as the one mounted on the blade of the bulldozer in the background.
Gravity is at work here.
As both trucks move to the left, a trail of pavement is left. The heavy roller further compacts the paving material. Moving the stands The football stands, seen at the left in this picture, must be moved to the foreground area at the right. They will sit on a concrete slab. The form will be removed after a couple of days.