Sight alignment is exactly that. The front and the rear sight must be aligned together and with the target. Typical open sights are found in the following styles: Front Post and Rear Open; Front Post and Rear Aperture; and Front and Rear Aperture.
The Front Post/Rear Open configuration is probably the most common and familiar to the beginning shooter.
Proper alignment places the front sight exactly in the center of the rear sight’s opening. The top of the front sight should be exactly level with the top of the rear sight. The same principle applies to other variations. With the Front Post/Rear Aperture, the Front Post must appear in the absolute center of the circular aperture of the rear sight. Equal amounts of “daylight” should be seen to either side of the front sight.