Character Selection Menu for 2D Game

I was wondering if anybody could help me figure out how to do a character selection menu like the one in Timber man. I already have the main menu but I can not figure out how to do the character select menu. I tried using the code that I found in one of he Forums but I can't get it to work. also how would I add GUI buttons to switch between characters? and yes I have tried google, but i cant find anything that helps.

  enter code here//character prefabs
     public Transform character0;
     public Transform character1;
     public Transform character2;
      
     //you can change this in editor or from script to load a different character
     public int characterChoice = 0;
      
     void  Awake (){
         //with this, the gameobject you attached the script not gonna get destroyed after loading
         DontDestroyOnLoad (transform.gameObject);
     }
      
      
     void  OnLevelWasLoaded ( int level  ){
          if(characterChoice == 0){
           Instantiate(character0, Vector3 (0f, 37.40265f, 0f), Quaternion.identity);
      
          }
          else if(characterChoice == 1){
           Instantiate(character1, Vector3 (0f, 37.40265f, 0f), Quaternion.identity);
          }
          else if(characterChoice == 2){
           Instantiate(character2, Vector3 (0f, 37.40265f, 0f), Quaternion.identity);
          }
     //etc if you have more options
     }