A couple of additional tips:
Once you cut your mask, in this case the flower, you can use a small piece of removable adhesive to keep it in place, or use a sticky note.
When they stamped the large background image and stamped it off on the scrap mat, this was done so your image would be lighter, and the misting with water created a watercolor look. You can purchase the Stampin' Spritzer, seen on page 163 of the Annual Catalog at my Online Store.
This is a fun technique that lets you create images that make people ask "how did she do that". It is really nice if you want to create a large bouquet of flowers, or like in this video, a nice background that just silhouettes your image. I will try to post a card this week using this technique.