Sorry for the late response, I believe you could maybe call an action on creation for the object to set it's position to a random integer within window.minimumX (far left of screen) and window.maxX (far right of screen)
Example: On Created (object.Platform) - Platform.Set X (rand.int(0-800))
// So that it chooses a spot between those two, im not exactly sure how to call a random number so you will have to find that out on your own.
Have fun!