Mix up your pudding with the milk first, and chill in the refrigerator for at least 5 minutes. This will prevent the bananas from too much air exposure, when you start layering, and turning a yucky color.
Then start layering a 9 x 9 baking dish with your ingredients.
First, a layer of vanilla wafer cookies, then a layer of sliced banana, and then half of the pudding mixture.
Repeat another layer of cookies, bananas and the rest of the pudding.
Cover and refrigerate till you're ready to serve. Then top with about 1/2 cup of crushed vanilla wafers to make it look pretty.