Pass a SkillCoolDown value to the method as a unique parameter

I have a Skill base class and 2 separate Skill classes that inherit from the Class Skill. Each skill has its own SkillCoolDown value. I set the CoolDownManager Class that is visualising the cooldowns for the skills, but I don't understand how to set the SkillCoolDown value to the manager which is different for each skill. Would appreciate the help.

public class Skill
{
    private string skillName;
    private int skillDamage;
    private string skillDescription;
    private int skillCoolDown;

    public string SkillName {get;set;}
    public int SkillDamage {get;set;}
    public string SkillDescription {get;set;}
    public int SkillCoolDown {get;set;}
    public Skill () {}
} 

public class CoolDownManager : MonoBehaviour
{
    public Skill skill;
    private Stopwatch cooldown;
    private Button button;
    private Image fillImage;
    private int skillCoolDown;


    public void OnSkillUse(Button btn) {

        skill = new Skill();  // HERE THE VALUE SkillCoolDown SHOULD BE IMPLEMENTED AND I WANT SOMEHOW TO SHOW WHICH SKILL HAS BEEN USED.

        button = btn.GetComponent<Button>();
        fillImage = btn.transform.GetChild(0).gameObject.GetComponent<Image>();
        btn.interactable = false;
        fillImage.fillAmount = 1;
        cooldown = new Stopwatch();
        cooldown.Start();
        StartCoroutine(CoolDownAnimation());
    }


    private IEnumerator CoolDownAnimation() {
        while(cooldown.IsRunning && cooldown.Elapsed.TotalSeconds < skill.SkillCoolDown) {
            fillImage.fillAmount = ((float)cooldown.Elapsed.TotalSeconds / skill.SkillCoolDown);
            yield return null; 
        }

        fillImage.fillAmount = 0;
        button.interactable = true;
        cooldown.Stop();
        cooldown.Reset();
    }
}

And here is example of the Skill class from where the value SkillCoolDown should be passed.

public class BasicAttack : Skill
{
    public BasicAttack() 
    {
        SkillCoolDown = 2;
    }
}