To do this you need to remove the window winder handle, arm rest and opening handle. With these out of the way, and any visible screws taken out, the door card can be popped off - its held in place by (yes you've guessed it) plastic poppers. Behind this there should be a plastic weather sheet which you peel away to access the window guides. If you post back, I'll need to know how old the Micra is.
John, January 2008