Show Ad every so often?

Unity Engine
1

Ok so I have managed to integrate ads into my project but I don’t have alot of experience with c#.

So I just wanted to know if anyone would know how to change a script that creates an button (to show an ad) so the ad would appear every amount of time set. e.g 5 minutes.

Here is the script example:

using UnityEngine;
using System.Collections;
using UnityEngine.Advertisements;

public class ShowAds : MonoBehaviour
{
    void OnGUI ()
    {
        Rect buttonRect = new Rect (10, 10, 150, 50);
        string buttonText = Advertisement.IsReady () ? "Show Ad" : "Waiting...";

        if (GUI.Button (buttonRect, buttonText)) {
            Advertisement.Show ();
        }
    }
}
2

Sorry wrong Forum