The .write ( ) command is actually a method that requires a parameter string to tell it what to write. Don't get confused about the terminology here, soon you will pick it up because you will see that it is very logical. In summary, methods simply define the behavior of objects by providing steps that an object should follow. If the properties of an object define what the object is going to look like, the method tells it what to do.
You may have already realized that you have already created an object, defined its properties, and provided a method actor in LESSON 2 when you created the alert box.