This is about on how to move a platform( or any object) forth and back from point to point. In this example we will use a MoveTowards method.
public Transform pos1, pos2; float speed = 5; Vector3 nextPos; void Start() { nextPos = pos1.position; } void Update() { if(transform.position == pos1.position) { nextPos = pos2.position; } if (transform.position == pos2.position) { nextPos = pos1.position; } transform.position = Vector3.MoveTowards(transform.position, nextPos, speed * Time.deltaTime); }