First make sure the button on the bottom of the lock assembly is depressed and the key is turned passed the on position, holding the button in, like it was when ya took it off. Look down into the mechanizium on yer bike and make sure the slot in the bottom is aligned so that when you insert the lock itself, the tab on the lock lines up with the slot, it should be a little past the on position and your bike should be on. If ya got all the other little spacers,tabs and springs lined up all you should have to do is press the lock down, turn the key back and everything should funtion properly. If not ya probobly have turned the slot in the lock the wrong way at some point, it's kinda tricky ta find the right spot cuz the switch has detents that work 360 deg. You'll have to do some trial and error until ya get it, but as the guys have told ya "Don't force anything!" patience and persistance is what ya need, don't let this thing get ya.