You use overriden method, when you want your subclass to do something in a different way than the superclass in the same method. For example, if you have Animal class and the makeSound() method that will just print out "making sound", then after if you create Cat class which extends the Animal, you surely want the objects of class Cat make another sound, like "miaaaaaaaaaau!!". In such cases you override the method makeSound() in the Cat class.
Overloaded method you use, when you need another method with the same name, but taking different list of arguments... I think the use of it is quite obvious... While the post above had given you a nice example of overriding, I'm giving the example use of overloading here, Dude .