what he means is.. you defined a function, in order to execute the function you need to call it. All a function is needed for is for code reuse, say you want a function that grabs the name of the user, its much easier to make a function for this and call the function instead of type all the code to grab the persons name, get it? So what you did is create a function, but you never called it.
So either call the function, like this
function_name_here();
Or just remove the line that says, hey this is a function, and it should work.