How to make ad appear after a few seconds?

What is a simple script so that an unity ad shows up after a certain amount of time has passed?

Is it possible to do it with a Coroutine? If so how?

It’s quite easy to do with a coroutine indeed, with WaitForSeconds.

IEnumerator delayedShowAd(float delay)
{
  yield return new WaitForSeconds(delay);
  Advertisement.Show();
}

void ShowAd(float delay) 
{
  StartCoroutine(delayedShowAd(delay));
}