Get a helper to move the steering wheel slowly from lock to lock while you inject grease with a grease gun. This will help circulate the lubricant. Do not swing the steering violently on rack-and-pinion systems when the wheels are off the ground. The sudden pressure surge inside the rack housing may damage the rack gaiters.
See that the gun is filled with grease of the correct grade, and inject each nipple until fresh grease exudes from the joint. Wipe the nipple clean. Do not over-grease a ball joint; the rubber seal round the top of the joint can easily be forced out by excess pressure from a grease gun.