Here is one way to look at it.
Hopefully it makes some sense.
//create all of your sprites but make only the ones you need for the start screen visible.
// you can either make the x and y value of the sprite such that the will not appear on the screen
// or set visible = false
//this var will tell us what screen to draw
var screen = "start" ;
if(screen == "start")
//This condition will be true at the start and here is where all of the code to draw the start screen
//We also need a mechanism to change the value of screen to "playing".
//This could be a timer var reaching a certain value or a MousePressedOver(sprite) function as a
//condition to an if statement.
else if(screen == "playing")
//here is all of the code for when the game is playing
//we will have to first, hide all of the sprites that we don't want to see from the "start" screen again
//either by moving them off the screen sprite.x = 500 or by setting sprite.visible = false ;
//This could be where the end game screen code is.
}//end of the draw function.