I take a premade graham cracker crust, line the bottom with sliced bananas (if I have any), cover with banana pudding and chill. When ready to serve I top with whipped cream or cool whip.
My grandma used to make her own crust by crushing Vanilla Wafers with a little butter and sugar, then add the bananas and whipped cream. She never measured anyting, so I can't tell you how much to use, but any cookie crust recipe should work.