Sounds like the drive belt is broken. Check this by removing the top of the dryer- just 3 screws at the back then slide the top backwards to remove. The belt will be clearly visible & come away if broken.
To repair you need to remove top & back of the dryer, all those screws, release the split pin & washer from the drum centre axle. Free the drum axle from the dryer back panel - at which point it will drop a few inches. You've then got to fit a new belt - line on drum should be clear - belt has to go around motor spindle and between guide pulleys.
Rob in Purley, August 2008