Sights are an essential part of most types of archery today. They assist in attaining repeatability from release to release, however they do not compensate for bad form with one possible exception covered later.
All sights operated in essentially the same way by providing a moveable front reference point to align with the target. This reference point - the pin - is moved up or down to compensate for the gravity caused drop that occurs after release. Usually a scale on the sight is calibrated as a range. This calibration is dependent on the bow's dynamic draw curve and the arrow's characteristics.
Attach the sights are per sight and bow manufacturer's recommendations. Things to watch:
that the vertical movement is parallel to the bow's un-drawn string, shimming with oiled paper or other material if necessary,
that the lowest part of the sight barrel assembly is at lease 30 mm above arrow axis to ensure fletch clearance with a flexing arrow,
that the scale arm will allow sufficient sight pin travel.
For recurves with long sight arm to assist in cancelling the bow hand torqueing effect, set the optimal sight arm length as below. (This can be done later however as a fine tuning exercise).
The best method to determine the optimal peep location requires an assistant. With the eyes closed, draw the bow in a horizontal position and move the head and anchor point about until it feels really comfortable in a firing position with good anchor. Do not dry-fire. Prefer a head-up with minimal head lean forward or sideways. Open your eyes and have your assistant mark the string at the same level as your eye. The line between this mark and your eye should be parallel to the draw arrow. Repeat several times to get an average for your peep location.
Draw the bow again with arrow and have your assistant measure the proposed peep height to the center of the arrow axis. This should be 200-250 mm for an adult. If it is too low, your head form will be poor and you may run out of sight adjustment for longer ranges. If it is too high the stretching may become uncomfortable with time. That said, it is better to err on the high side rather than the low.
Insert the peep as described in many books and internet sights but do not tie in until you have let loose some short range shots to confirm the feel is good. (Use protective glasses as there is a small possibility of the peep energetically coming free on release). If all seems ok, tie in the peep.
As your experience and form develops you should periodically confirm your peep is well located with the closed eye test. While moving the peep is not particularly difficult, doing so may de-tune the fine tuning of the bow in the vertical plane, introducing a little porpoising.
The physics of the bow and sight show that it is possible to place the
sight pin at a distance forward of the grip that tends to cancel the
effect of the archer torqueing (twisting) the bow with the bow hand.
The physics of this problem are a bit complicated as it involve the
internal ballistics of the bow and arrow, and the geometry of the sighting
arrangements. For this reason calculating the theoretical location is best
avoided and an experimental approach is taken.
Set the effective sight arm to minimum length and range the sights to say
40 m. Being careful not to torque the bow, shoot an end. Then with some
deliberate torquing to the right (i.e. clockwise from above) shoot another
end. This second group will be to the right of the first group.
Move the scale arm out say 150 mm and repeat the above two group test.
Continue this process until the first and second groups merge. You will
need to reduce the step size in the movement of the scale arm along the
sight arm as you get closer the optimal point.
FlyingSticks requires several measurements so that it may calculate the range-tape scale accurately. Three dimensions are required:
peep or eye to arrow axis,
peep or eye to sight point,
peep or eye to nock distance along arrow axis.
These measurement, should be done with sub-millimeter precision.