Pulao follows a fairly simple cooking style wherein the meat is cooked first (or the vegetables are sautéed, in case of a veg pulao), the rice is added and then both are cooked together in a predetermined quantity of water. To make a biryani, a "layering" technique is used. The meat is cooked separately with spices, while the rice is par-boiled. The two are then arranged in layers in a pot and cooked (dum) on low heat.
So watching complete variety of both keep watching the recipes followed...