How do I change the text in unity3d with a script that I can not remove?

I have a problem with unity3d and I do not know how to solve it.

I have a certain script

using UnityEngine;
using System.Collections;
using UnityEngine.SceneManagement;
using UnityEngine.UI;

public class CharacterSelector : MonoBehaviour

{
    [SerializeField]

    private Text bio1 = null;
    private Text data2 = null;
    private Text name = null;
    private Text subname = null;
    private GameObject[] characterList;
    private int index;

    private void Start()
    {
        characterList = new GameObject[transform.childCount];

        for (int i = 0; i < transform.childCount; i++)
        {
            characterList[i] = transform.GetChild(i).gameObject;
            foreach (GameObject f in characterList)
            {
                f.SetActive(false);
                if (characterList[0])
                    characterList[0].SetActive(true);
            }
        }
    }

    public void ToggleLeft()
    {
        //desligar o modelo atual
        characterList[index].SetActive(false);
        index--;
        if (index < 0)
            index = characterList.Length - 1;
        //ligar o modelo atual
        characterList[index].SetActive(true);
    }

    public void ToggleRight()
    {
        //desligar o modelo atual
        characterList[index].SetActive(false);
        index++;
        if (index == characterList.Length)
            index = 0;
        //ligar o modelo atual
        characterList[index].SetActive(true);
    }

    public void COnfirmButton()
    {
        if (index == 0) 
        {
            SceneManager.LoadScene("NeroRoom");             
        }
        if (index == 1) 
        {
            SceneManager.LoadScene("Menu");
        }

    }
    public void ChangeText() 
    {
        if (index == 0) 
        {
            name.text = "Mac Logan";
            subname.text = "O coração valente";
        }
    }
}

This script is linked to a gameobject that has the characters of the game depending on each one the biography and specifications will change. This can be seen in the Public void COnfirmButton.

So how do I change a text depending on the characters that are appearing?

The part of [SerializeField] to private Text subname = null ; I saw it in a tutorial but it did not work out.