Open the back of the camera. Remove the film rewind knob by pulling it while squeezing the bits that go into the film canister. Or if you want to be more gentle with your viv, remove the small screw in the centre of the winder and take it apart that way.
Undo and remove the three screws from the positions shown below. Note the smaller screw goes in the side of the camera.
Remove the silver part of the case. To do this you need to push in the little rewind button and hold down the shutter button. Start at the rewind knob end of the camera as show. Opening is a bit tricky, be patient and don't force it, it will come apart eventually!