The Xbox One controller features two analog sticks, a directional pad, left and right triggers, back and start buttons, a Guide button, and both a left and right bumper. On the top of the controller are four LED lights that correspond to the player number (1-4) assigned to the controller. The left stick is referred to as the LS or Left Stick while the right stick is called the RS or Right Stick. Each analog stick can be pressed down to perform a click function.
The LS on an Xbox One Controller lets you move around in most games. In first person shooters it will control your character’s movement, in racing games it will drive your car forwards or backwards, etc. The RS is generally used for looking around or aiming. In first person shooters it will aim your gun wherever you move it and in racing games it will control your steering.
Most Xbox One controllers also have what’s called an “LS click” and an “RS click” which act as extra buttons you can press down with either thumbstick. These are usually mapped to things like sprinting in first person shooters or using nitro boosts in racing games.