Bolt hinge plates to the end posts, securing them with nuts and washers. Most gateposts will have pre-drilled holes for the bolts to run through, but you may find it necessary to drill them yourself. In that case, position the hinge plates at such a height that the gate will have a minimum 4-inch clearance above the ground.
Attach 90-degree anchor hinge bolts to the gate itself, sliding them through the pre-drilled holes and rotated so the hook portion of the bolts point downward. Secure with nuts and washers.
Place a ball bearing in the barrel of each hinge plate and lift the gate into position, sliding the hinge bolts' heads into the barrels. Tighten the nuts on the hinge bolts until the gate hangs level and grease the hinges.