How can I use 'buy character button'?

Hi, so i made this system in 3d. I used scriptableObjects for that. first you have to put the characters script on a empty object. If you done that you have to add characters in character list, to do that you have to rightclick in your assets folder and go to c(create > character). if you done that u have to declare a character object in there and the gold amount(how much it cost) (IMPORTANT: the object must have the dontdestroyonload script!!!). After u done that u have to add this character object to the characters list. If you done all that u have to make some buttons (Rightclick in scene > UI > Button). In the button there is a "component" called "On Click()". in the bottom right corner of this component there is a "+", you have to click on that. In the object " section" u have to add your empty Gameobject with the characters script on it. If you done that u have to click on Function and go to the character section. In there u can select functions of the script, like "next" or "buy". that should be it.

Add this script on a empty GameObject using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI; using UnityEngine.SceneManagement;

 public class Characters : MonoBehaviour
 {
     public List<Character> characters;
     public int selectedCharacter;
 
     public int charactersInList;
 
     public int gold = 450;
     public Text goldText;
 
     public GameObject previewObject;
 
     public bool canStart;
 
     void Start()
     {
         previewObject = Instantiate(characters[selectedCharacter].characterObject, transform.position, transform.rotation);
 
         goldText.text = "Gold:" + gold.ToString();
 
         selectedCharacter = PlayerPrefs.GetInt("selectedCharacter");
 
         Refresh();
     }
 
     public void Refresh()
     {
         charactersInList = 0;
         for (int i = 0; i < characters.Count; i++)
         {
             charactersInList++;
         }
         charactersInList--;
     }
 
     void Update()
     {  
         if (Input.GetAxis("Mouse ScrollWheel") > 0)
         {
             Next();
         }
         else if(Input.GetAxis("Mouse ScrollWheel") < 0)
         {
             Back();
         }
     }
 
     private void SelectSkin()
     {
         if(previewObject != null)
         {
             Destroy(previewObject);
             previewObject = Instantiate(characters[selectedCharacter].characterObject, transform.position, transform.rotation);
         }
         Debug.Log("m");
     }
 
     public void Next()
     {
         if (selectedCharacter < charactersInList)
         {
             selectedCharacter++;
             SelectSkin();
         }
     }
 
     public void Back()
     {
         if (selectedCharacter > 0)
         {
             selectedCharacter--;
             SelectSkin();
         }
     }
 
     public void StartGame()
     {
         if (canStart)
         {
             PlayerPrefs.SetInt("selectedCharacter", selectedCharacter);
             SceneManager.LoadScene(1, LoadSceneMode.Single);
         }
         else
         {
             Debug.Log("you have to pay First!");
         }
  
     }
 
     void Buy()
     {
         if(gold >= characters[selectedCharacter].Gold)
         {
             gold -= characters[selectedCharacter].Gold;
             canStart = true;
             StartGame();
         }
     }
 }

Dont do this script on any object, it just have to be in your asset folder(to create characters click (create > characters)

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 [CreateAssetMenu]
 public class Character : ScriptableObject
 {
     public int Gold;
     public GameObject characterObject;
 }
 

To every character visual object u have to add this script, so the object dont disappear after loading into a new scene

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class DontDestroy : MonoBehaviour
 {
 
     public void Awake()
     {
         DontDestroyOnLoad(this.gameObject); //Other stuff 
     }
 
 }

I hope i could help if you have any questions or u run into some issues with these scripts, tell me, i will give my best to help you :D