Remove your cake topper from the sealed bag and gently peel off the clear top sheet.
If you're using fondant icing, use a pastry brush to lightly wet the top of the cake around the edges. This will help the cake topper to stick to the fondant. Don't make it too wet or the topper, particularly if the fondant is a colour (not white) as too much water will make the topper transparent.
Carefully peel the cake topper from the backing sheet and place it on the cake. Try not to touch the picture!
Tap the edges to seal the cake topper on the cake.
You can finish it off by adding some sprinkles or pipe a bit of icing around the edges.