Instructions
Turn on the Xbox 360 console.
Press the "Connect" button on the console. On the original Xbox 360, this is located to the right of the memory card ports. On the Xbox 360 S, it is located to the right of the "Power" button.
Tap the "Connect" button on the controller you wish to connect. The button is located on top of the controller, by the headset port. Connection is complete when the controller's green lights stop flashing.