Bolt hinge plates to the inward side of the gateposts at such a height that the gate will hang with a minimum clearance of 4 inches above the ground. Orient both plates so the barrel portion points upward.
Run 90-degree hinge bolts through the predrilled holes on the side of the gate, securing them with nuts in such a way that the hook points downward.
Grease the hinge plates and the hinge bolts. Drop a ball bearing into the barrel of each plate. Lift the gate piece with the help of an assistant and lower the hooks of the hinge bolts into the barrels. Tighten or loosen the nuts on the hinge bolts as necessary for the gate to hang level. Swing the gate back and forth to ensure freedom of movement, adding more grease if required.