Article: Slide your casserole dish or baking pan onto one of the upper shelves in your refrigerator where you’ll be able to keep an eye on it. Make sure the shelf you pick out is perfectly flat so the Jello sets in an even layer.  There’s no need to wait for your Jello to set completely—you just want to leave it in long enough to let it solidify to the point where you can add another layer without the colors mingling. If the shelf you use is crooked, your Jello layers may come out thicker on one end than the other, which could throw off the look of your rainbow. Use a table knife to carefully slice the single sheet of Jello into precise squares. Aim to make each square the same size so you won’t be left with any thin slivers or oddly-shaped pieces. Enjoy!  If you’re serving bigger kids and adults, measure your squares to be about 2–3 inches (5.1–7.6 cm) apiece. For smaller children, 1–2 in (2.5–5.1 cm) servings should be plenty.  Cover your leftover Jello and store it in the refrigerator. It should stay good for a week or longer.

What is a summary?
Chill the first layer of Jello in the refrigerator for 25-30 minutes. Cut your rainbow Jello into squares before serving it.