4 spawn locations, 4 prefabs

Good evening all,

I'm trying to set up a script that spawns 4 random prefabs at 4 locations i have set up as spawn locations. When I play the game, the objects all instantiate but two errors occur... 1) spawns 4 objects of the same color (but the color can change every time I rerun the game but still 4 of the same color) 2) they all spawn in the same location.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class BucketSpawn : MonoBehaviour {
 
     [SerializeField]
     private GameObject[] spawnLocations;
 
     [SerializeField]
     private GameObject[] bucketPrefabs;
 
     private int bucketsOnScreen = 0;
 
     // Use this for initialization
     void Start () {
         int rndSpawnLocation = Random.Range(0, 3);
         int rndBucketSpawn = Random.Range(0, 3);
 
         while(bucketsOnScreen < 4) {
             Instantiate(bucketPrefabs[rndBucketSpawn], spawnLocations[rndSpawnLocation].transform);
             bucketsOnScreen++;
         }
     }
     
     // Update is called once per frame
     void Update () {
         
     }
 
 }

i've literally spent hours trying to figure out whats going on, and why it wont actually fetch a position for each individual piece rather than obtaining a random position for everything and setting it for all 4 pieces. i've tweaked it so much that now I cant even get them to spawn on the screen anymore. any help would be greatly appreciated.