Setting is one of the most integral parts of volleyball because without having a set you cannot get a hit and without a hit you are less likely to get a point. The basic rules for setting are that you cannot double touch which basically means that you have to set the ball with both hands simultaneously. If you fail to do so the other team gets the point. The form for setting is very simple however there are many ways one can start to set the simplest way is to form a triangle with your index fingers and your thumbs and have someone toss the ball like a rainbow pass and instead of setting it just catch the ball and hold it. As soon as the ball touches your hands let your arms go back towards your face then push your arms out away from your face and as soon as they are fully extended flick your wrist away from one another.
A tip to help in prove your setting and prevent you from getting called on doubles is to set with a basketball against the wall or a medicine ball to improve your forearm and wrist strength.