Megan explains the process perfectly. I, on the other hand, did not follow the tutorial perfectly. Or so it would appear. My scallops pull and pucker a tiny bit. But I swear I did it just the way she outlines. I added my scallops to a very simple skirt. A big rectangle of fabric with a casing sewn at the top. The casing is made from the same yellow fabric as the scallops. I threaded elastic through the casing.
Oh well. I still think it is cute. And so does Sweet Pea. Boy, she sure has trouble standing still!