Press and Hold "Set" button until yellow light is solid, Press the button you want to program (Menu, Mute, AV/TV), Yellow light will start to blink.
Now point the remote that you want the X5 remote to learn from at the front of the X5 remote (Front to Front) and press the button that you want the X5 remote to learn. The yellow light will blink fast and then turn solid if it has received the signal. Now press and hold the "Set" button until the yellow light turns off. Test to see if the X5 remote has learned the function of the button you just programmed. If it does not work the first time try once again. Make sure that the yellow light blinks fast after pressing the button you want it to learn as this indicates that the X5 remote has learned the function.
The X5 can only learn IR (Infrared Signals), most remote controls use IR, but some of them use radio frequencies and cannot be learned by the X5 Remote Control.