Sitting in the car, wind the sunroof half way back, grab hold of the headlining on its forward edge, and pull firmly in a downwards motion, this will release the 4 or 5 clips, that attach the lining to the sunroof itself, you can then wind the sunroof to the almost closed position, but slide the headlining backwards into the roof.. this will reveal all the inner workings of the sunroof, to refit, open halfway again, pull the lining forward, and clip back into place
HTH
Thom