An easy way to make layered jello is to add Cool Whip to the liquid after all of the water is added. I don't measure but I use about 1/4-1/3 of the Cool Whip container. Mix it in with a hand whisk and pour into mold (sometimes I use a glass 9X13 pan because it makes more and looks pretty cool

). The Jello will self-separate making a regular clear layer on the bottom and a creamy layer on the top. I usually add some mini-marshmallows. Once that layer is set (a few hours) I do the same thing with another flavor. A 9X13 pan will hold 4 small boxes of Jello so you end up with 8 different layers.