How to enable a children of a clone object?

I hold my clones in a list for GUI operations.

button = Instantiate(BlackBox, Vector2.zero, Quaternion.identity) as GameObject;
buttons.Add(button);

How to enable ArrowRight in this situation:

84611-1.png

I want to reach ArrowRight to enable it. I tried variations of this kind of methods:

buttons[index].gameObject.transform.GetChild(1).gameObject.SetActive(true);

Components here:
84615-2.png

How can it be implemented? Thanks.

Solved:

buttons[index].transform.GetChild(1).gameObject.SetActive(true);