How do i get my spare vw golf key to work?

My baby has 'HIDDEN' my vw golf car key and I have the spare but when I put it in the ignition the electronic immobiliser light comes on and the car won't start, does anybody know what I have to do???|||as a temporary fix too get the car running so you can go too vw too have key programmed properly put key in ignition and turn on but dont start leave for ten minutes then start the car up the imobiliser will have relearned the key but will req programing|||Then its not the right spare or its been decoded, you'd have to contact VW.|||better asking dealer or vw car forums|||you need the electronic chip from key that is lost,contact the garage you bought it from or vw agent explain situation supply proof of purchase etc and they will have vw send replacement chip to insert in key fob