When we write a script, we are making lines of code that the computer is going to execute, one line at a time. As we write our code, there will be things that we want our game to execute more than once. For example, we can write a piece of code that adds two numbers. Suppose our game needs to add those two numbers a hundred different times during gameplay. So you'd say, "Wow! I have to write the same code a hundred times to add two numbers together? There has to be a better way."
Let a method take away your typing pain. You just have to write the code to add two numbers once and then give this chunk of code a name, such as AddTwoNumbers(). Now, every time your game needs to add two numbers, don't write the code over and over, just call the AddTwoNumbers() method.