How do I show an admop interstitial ad after number of clicks on the item-views of recyclerview?

Question

In some apps that are similar to my app, they have this thing when the user clicks on the item views of the recycler view randomly for 3 or 4 times and it displays an Admob interstitial ad for them before moving to the next activity or fragment. I would like to do the same, like showing the ad for the user after he clicks randomly for 3 or 4 times on the item views and when the ad is closed it should move to the next fragment. How do I do this kind of idea?

P.C. I am using navigation components to navigate between the fragments and you can use java or kotlin, I understand them both.

**Here is my recycler view code **

    class NewsListAdapter(
    val context: Context,
    val news_list: ArrayList<NewsListViewModel>,
    val view: View
) :
    RecyclerView.Adapter<NewsListAdapter.vHolder>() {


    var inum = 1
    var countNum = 0
    private lateinit var OverLoad: OverLoad
    private lateinit var mRef: DatabaseReference

    private var mInterstitialAd: InterstitialAd? = null
    private final var TAG = "NewsListAdapter"


    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): vHolder {
        val view = LayoutInflater.from(parent.context)
            .inflate(R.layout.news_list_design, parent, false)

        return vHolder(view)
    }

    override fun getItemCount(): Int {
        return news_list.size
    }

    override fun onBindViewHolder(holder: vHolder, position: Int) {

        val newsList = news_list[position]

        val image = newsList!!.image
        val imageView = holder.news_image

        Glide.with(this.context)
            .load(image)
            .into(imageView)
        holder.news_title.text = newsList.title
        holder.news_desc.text = newsList.desc
        holder.news_date.text = newsList.date
        holder.news_type.text = newsList.type


        val shared = context.getSharedPreferences("LatestNewsSaving", Context.MODE_PRIVATE)
        val editor = shared.edit()

        editor.putInt("fav_blue", R.drawable.ic_favorite_blue)
        editor.putInt("fav_border", R.drawable.ic_favorite_border)
        // editor.putInt("count_newsList_num", countNum)
        editor.apply()


        interstitialAd()

        PushDownAnim.setPushDownAnimTo(holder.card_view)

            .setOnClickListener {

                countNum += 1
                editor.putInt("count_newsList_num", countNum)
                editor.apply()

                if (shared.getInt("count_newsList_num", 0) == 3) {
                    countNum = 0

                    if (mInterstitialAd != null) {
                        mInterstitialAd?.show(context as Activity)
                    } else {
                        Log.d("TAG", "The interstitial ad wasn't ready yet.")
                    }

                    val passData = LatestNewsFragmentDirections
                        .actionLatestNewsFragmentToNewsDetailFragment(news_list[position])
                    Navigation.findNavController(view).navigate(passData)
                } else {
                    val passData = LatestNewsFragmentDirections
                        .actionLatestNewsFragmentToNewsDetailFragment(news_list[position])
                    Navigation.findNavController(view).navigate(passData)
                }


            }
    }

    fun interstitialAd() {

        var adRequest = AdRequest.Builder().build()
        InterstitialAd.load(context, "ca-app-pub-xxxxxxxxxxxxxxxxx", adRequest, object :
            InterstitialAdLoadCallback() {
            override fun onAdFailedToLoad(adError: LoadAdError) {
                Log.d(TAG, adError?.message)
                mInterstitialAd = null
            }

            override fun onAdLoaded(interstitialAd: InterstitialAd) {
                Log.d(TAG, "Ad was loaded.")
                mInterstitialAd = interstitialAd
            }
        })
    }

    class vHolder(view: View) : RecyclerView.ViewHolder(view) {

        val news_image = view.findViewById<ImageView>(R.id.news_image)
        val news_title = view.findViewById<TextView>(R.id.news_title)
        val news_desc = view.findViewById<TextView>(R.id.news_desc)
        val news_date = view.findViewById<TextView>(R.id.news_date)
        val news_type = view.findViewById<TextView>(R.id.news_type)

        val card_view = view.findViewById<CardView>(R.id.newsListCard)
        val favourite_add = view.findViewById<ImageView>(R.id.favourites_add)


    }

}