Sprite Basic has 3 predefined methods, called directly by the system. You don't have to call them in your code. Those methods are OnInit(), OnUpdate(), OnCollision(). Outside those methods is the Global Section, where you declare you global variables (variables available throughout all methods of a scene) and the data to be read with 'read' basic command.
You can also define your own methods. Those won't be called explicitly by the program, you'll have to call them from OnInit, OnUpdate or OnCollision