The Scout sign is made by holding your right hand at shoulder height in the position shown on the right. It is used whenever someone makes or renews their Scout Promise. The three outstretched fingers represent the three main parts of the promise and the circle between thumb and little finger represents the world-wide family of Scouting. The Scout salute is made by holding your right hand in the same position, but with your first finger pointing to your right eyebrow (and your elbow out). It is only used when in full uniform as a formal greeting or sign of respect e.g. when hoisting/breaking open the union flag.
As we know Scouts across the world all greet each other with a left-handed handshake and that it is a sign of trust and friendship but why did and how did Baden Powell come to decide to use it when he formed the Scout Movement There is a story that when Baden Powell entered Kumasi, the capital city of the Ashanti he was met by one of the Great Chiefs of the Ashanti, he saluted them and then offered his right hand out as a sign of friendship, but the Chief transferred his shield which he held in his left hand to his right which contained his spear and offered his left hand as a sign of friendship. When asked why Baden Powell was told that by offering his left hand which traditionally was used to hold a shield for protection he was showing his trust to his enemy or friend for with out the shield for protection he was open to attack.