How do I switch characters?,How do I switch caracters? I have this code that works but I cant figure out how to make it work if I have more than 2 characters. Please help.

You ought to look up some tutorials around using arrays and/or lists as when you have a large or unknown number of things to save that are related to each other, is prime use! Here's an example of how you might solve your problem:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class CubeSwitcher : MonoBehaviour {
     string[] cubePrefix; //array of prefixes to append to "cube" to lookup gameobject names
     GameObject[] cubes; //the cubes that we find
     int playerCount; //the number of cubes found
     int playerSelect; //the current active cube
 
     void Start () {
         cubePrefix = new string[3]{"L", "T", "Z"};
         List<GameObject> c = new List<GameObject>();
         
         playerSelect = 0;
 
         for(int i = 0; i < playerCount; i++){
             GameObject go = GameObject.Find(cubePrefix[i] + "Cube");
             if(go != null){ //if we didn't find the object, skip it!
                 if(c.Count == playerSelect){
                     go.SetActive(true); //if this cube is the currently selected one, activate!
                 }else{
                     go.SetActive(false); //else deactivate
                 }
                 c.Add(go); //then add it to our list and carry on
             }
         }
 
         cubes = c.ToArray(); //make our list an array
         playerCount = cubes.Length; //save the number of objects found
     }
 
     // Update is called once per frame
     void Update(){
         if (Input.GetKeyDown(KeyCode.DownArrow)){
             playerSelect = (playerSelect+1)%playerCount;
             // the '%' in 'a%b' returns the remainder after the division of a/b
             //hence this moves through our objects cyclically
             //(the last item goes back to the first item)
             //look up modulo arithmetic for more info!
 
             for(int i = 0; i < playerCount; i++){
                 cubes[i].SetActive(i == playerSelect); //set active if currently selected
             }
         }
     }
 }

hope that helps,

Scribe