How to make ad available after some time ?

okay , so I want to make my ads only be playable every 5 minutes
but i don’t know how to make that…

public void ShowAd()

{

    if (Advertisement.IsReady())
    {
        Advertisement.Show();
        PlayerPrefs.SetInt("Coins", PlayerPrefs.GetInt("Coins", 0) + 500);
        if (Controller.IsRunning == false) SetMenuScore();
    }
}

this is the code I’m using.

You just need to check the latest time your ad was displayed. If it was less than 5 mins ago, do nothing ; else, display it.

        [SerializeField]
        private float m_IntervalBetweenAdsInSecondes = 300f;

        public void ShowAd()
        {
            if (! Advertisement.IsReady())
            {
                return;
            }

            if (m_LatestDisplayedAdTime == -1f
                || Time.time - m_LatestDisplayedAdTime >= m_IntervalBetweenAdsInSecondes)
            {
                Advertisement.Show();
                m_LatestDisplayedAdTime = Time.time;
                PlayerPrefs.SetInt("Coins", PlayerPrefs.GetInt("Coins", 0) + 500);
                if (Controller.IsRunning == false) SetMenuScore();
            }
        }

        private float m_LatestDisplayedAdTime = -1f;