How do I figure out the value

Hi im new at CS2, recently i've been learning how to make flappy bird (tutorial and templates in CS2). Im doing it in 4:3 ratio portrait (480x640). I cant figure out the X and Y value for the parameter for system: create object for my top and bottom pipe. I have try lots of different values but it doesnt turn out right. Is there a method or a way to figure out the value.

// MOVE

every tick, -> PipeTop -> Set X -> Self.X-5. PipeBottom -> Set X -> Self.X-5

// CREATE

every 1 seconds ->

System -> Create object -> PipeTop

X = 400, Y = random(100,-100)

System -> Create object -> PipeBottom

X = 400, Y = PipeTop.Y+500

bobvu

Usually a .capx file helps to understand better your request

Anyhow, to get the x/y value for an object, you use Object.x/Object.y

Thanks a lot!!!