Public fields not showing in inspector

Public variables at line 8-9 are not showing in inspector. I was following the Unity 'Tanks!' tutorial and it said to drag/drop the slider and image into the fields, but I cannot find a way to show them in the inspector.Here is my code:

 using UnityEngine;
 using UnityEngine.UIElements;
 
 
 public class TankHealth : MonoBehaviour
 {
     public float m_StartingHealth = 100f;
     public Slider m_Slider;
     public Image m_FillImage;
     public Color m_FullHealthColor = Color.green;
     public Color m_ZeroHealthColor = Color.red;
     public GameObject m_ExplosionPrefab;
 
 
     private AudioSource m_ExplosionAudio;
     private ParticleSystem m_ExplosionParticles;
     private float m_CurrentHealth;
     private bool m_Dead;
 
     private void Awake()
     {
         m_ExplosionParticles = Instantiate(m_ExplosionPrefab).GetComponent<ParticleSystem>();
         m_ExplosionAudio = m_ExplosionParticles.GetComponent<AudioSource>();
 
         m_ExplosionParticles.gameObject.SetActive(false);
     }
 
 
     private void OnEnable()
     {
         m_CurrentHealth = m_StartingHealth;
         m_Dead = false;
 
         SetHealthUI();
     }
 
 
     public void TakeDamage(float amount)
     {
         // Adjust the tank's current health, update the UI based on the new health and check whether or not the tank is dead.
         m_CurrentHealth -= amount;
 
         SetHealthUI();
         if (m_CurrentHealth <= 0f && !m_Dead)
         {
             OnDeath();
         }
     }
 
 
     private void SetHealthUI()
     {
         // Adjust the value and colour of the slider.
         m_Slider.value = m_CurrentHealth;
         m_FillImage.tintColor = Color.Lerp(m_ZeroHealthColor, m_FullHealthColor, m_CurrentHealth / m_StartingHealth);
     }
 
 
     private void OnDeath()
     {
         // Play the effects for the death of the tank and deactivate it.
         m_Dead = true;
 
         m_ExplosionParticles.transform.position = transform.position;
         m_ExplosionParticles.gameObject.SetActive(true);
 
         m_ExplosionParticles.Play();
         m_ExplosionAudio.Play();
 
         gameObject.SetActive(false);
     }
 }

I am using Unity version 2019.2 and they are using an older version. i am only using 2019.2 because the tutorial download said it required that version. I am on a windows 10 computer and the editor is Visual Studio 2019. here is the video if you need it: https://youtu.be/XRzGfRkZrNM?t=2400