I love this technique. It is super easy and looks great!!
All you need are your stamps, ink, paper, and a piece of acetate (overhead transparencies).
Stamp your image on your cardstock, reink and stamp on the acetate.
Turn the acetate over (so the ink is down), link up with the image you stamped on the cardstock, carefully place the acetate down and gently rub.
You get a perfect mirror image!!
When I colored this one I used a light touch for the snowmen on the ice.
Hope these are clear enough directions for you.