Loading a script externally

How do I load a script externally? As in from streaming assets? I would like to make changes to the code. For example a simple code like this

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SetValue: MonoBehaviour
{
    private int value = 12;

    // Start is called before the first frame update
    void Start()
    {
        
    }

}