how to move object?

// se the movement parameters
Global number xA = 10
Global number yA = 20
Global number xB = 100
Global number yB = 120
Global number speed = 100

// some variables used in runtime
Global number dist = 0
Global number t = 0

System: trigger once
     -> System: set dist to distance(xA,yA,xB,yB)

System: t<1
      -> System: set t to min(1, dt*speed/distance)
      -> Sprite: set X to lerp(xA,xB,t)
      -> Sprite: set Y to lerp(yA,yB,t)[/code:3hpqub3m]
     
With that you have a clean, precise and constant motion from A to B
note that lerp isn't some magic function.
lerp(a,b,t)  = a + (b-a) * t
no more, no less. You give it 3 values, it gives you one.