A note on some Common Ingredients:
Since Cool Whip never freezes solid, I usually find that straight out of the freezer will do just fine. Cool Whip's texture can get a little runny if thawed completely, an it's preferable to work with it while slightly frozen. It usually comes in 2 sizes, a small one and a larger one. Either size will work just fine, but I usually get the larger one.
Canned crushed pineapple is the main form of pineapple used in Ambrosia, unless otherwise specified. You an also use pineapple chunks, for a chunkier, less uniform texture. Most recipes call for the pineapples to be drained before you use them. Some actually require that you save the drained juice to be used later.
Unless otherwise specified, bananas are always cut crosswise, into coin-shaped pieces. 1 banana per tub of Cool Whip is standard.
Mini marshmallows are a main ingredient of many forms of Ambrosia. I find that the rainbow-colored ones give a more festive look than the standard white ones. However, sometimes the array of pastel colors can clash with what you are making. Use your own discretion.Marshmallows generally come in only one size bag, if there is more than one size, just get whichever one looks the most common. If you can't find the marshmallows in your grocery store, they are usually located in the candy section; I've discovered this after hours of endlessly searching various stores!
Canned pre-made pie filling is a wonderful invention for the Habitual Ambrosia Addict, and the recreational user alike. PIe fillings come in a variety of flavors, apple, cherry, strawberry and blueberry being the most common. They generally come in one size, big enough to fit in one standard pie shell. If your local grocery store carries more than one size, just get the one that is the most prevalent.