A word of letters

Question

I have 2 arrays of buttons, the first array with a white text color (in the picture these are the upper fields), when you click on a button with a letter, this button disappears and assigns the text to a button with a white color. Ie, I need to press the button with a letter, it passes its text to the first free field-button, and she disappears. Every time a button is pressed, the free cell, the number in the array of button fields increases by one. A word of letters. I need to do this. I did so, but for some reason nothing happens, please tell me how it can be done?

 public Button[] LetterBtn;
public Button[] FieldBtn;

public void MoveS()
{
    for (int i = 0; i < LetterBtn.Length; i++)
    {
        for (int j = 0; j < FieldBtn.Length; j++) {
            LetterBtn[i].gameObject.SetActive(false);

            
            FieldBtn[j].GetComponent<Text>().text = LetterBtn[i].GetComponent<Text>().text;
        }
    }
}

// Start is called before the first frame update
void Start()
{
    for (int j = 0; j < FieldBtn.Length; j++)
    {
        FieldBtn[j].interactable = false;
    }
}