Instructions
Pick up a pack of spears, if you do not currently have any. Spears are often found on the ground in locations where you must defeat archers to move on.
Face the archer you want to kill. Hold down the "L" button to raise a spear and target the archer.
Press the "X" and "Square" buttons at the same time, while holding the "L" button, to throw a spear at the archer. Keep throwing spears until the archer falls.