You should only learn to shoot a bow from a trained person
.... it's not my fault if you shoot yourself in the foot.
But who knows when this knowledge may come in useful so here goes, a basic guide to archery technique, using a recurve bow; it will also work for a compound bow or a longbow
Capn's 'Seven Point' Guide to Archery
1. Line yourself up with the target so your body is perpendicular it. You shouldn't present your bottom towards the target as when you turn to aim towards it, you spine will be twisted in an awkward way
2. Take the bow handle in the hand you don't write with. That is to say it is usual to pull the bow-string back with your dominant hand; as this in fact stems from eye dominance it is not always the case. If you hope to continue with the sport and shoot to a high level, you should test for eye dominance and use that hand.
3. Place the arrow on the side of the bow opposite the hand you write with. At same time fit the nock of the arrow to the string with odd coloured fletching facing away from the bow handle, if they are all the same colour, rotate the arrow until just one fletching is facing away from the bow.
4. With your 'drawing hand', curl your first three fingers around the bow string, with you index finger above the arrow and the other two below the arrow. Put the string just behind the joint at the end of the fingers. As you pull back it should settle into the joint. Don't pinch the arrow or it may fall off as you draw the bow back.
5. Draw the bow back until the tip of your ring finger just touches the corner of your mouth. Keep you head in an upright natural position. This is known as the 'anchor point', if you keep this exactly the same from shot to shot, you can aim consistently by moving the hand you hold the bow with. A hint, as you draw the bow back, keep your drawing elbow above shoulder height, this makes you use the strong muscles in your back, your arms should not be taking the draw weight of the bow. What you want to achieve is a nice relaxed draw, using only the muscles needed and no more; one of things many beginners have to unlearn is the tension they put into the shot through setting themselves to 'resist' the weight of the bow.
6. You can then aim with the point of the arrow, adjust the aiming point according to where the arrow lies.
7. Let go. Try to relax as you let go, so that the tension in your back causes your drawing hand to fly back behind your head. In Zen and the Art Of Archery the process of the shot in described as rain-water falling from a bamboo leaf; the water builds and builds until quite naturally it is released to fall from the leaf. One of the signs of tension is that your drawing hand will stop and lock into position as soon as your let go of the string. If you think about it, all the power of the bow has been held by your fingers which have moved backwards as you have developed the shot. Having those fingers stop after you have let go of the sting would be as unnatural as a golfer stopping their swing on hitting the ball.
...and after the beginning you realise there is no end...
For beginners the first most important 'technicality' to get right is the anchor point (where this anchor point is will change with styles of archery, and the archers preference), work to get this consistent. Pay attention to the 'feel' of the shot, be mindful what you want is a relaxed technique, free from concerns and 'edges', you should feel it flow like unimpeded water.
As you progress and the physical process sinks into your muscle memory, shoot to a rhythm: nock, draw, aim... release. The whole process above doesn't take me more than five seconds, even in the wind.
There can be a tendency in a competion to look at your score and say to yourself 'All I need to get is 100 in the next dozen to win/beat my personal best!' Again be aware a good score is made one arrow at a time. Read the Way of Archery, for me that is the point of archery, you aim to shoot the arrow in the bow perfectly, what has gone before, or what might come after is not important.