create bell notification icon in the app bar and show the number of notifications received through firebase. on click of bell icon show a popup which shows the list of notifications.

I have implemented push notification logic in my project by using firebase and receiving notifications successfully.
Now I want to show bell icon at the top right of app bar in my activity and show number of notifications received, when we click on bell icon - open pop up which shows list of notifications received in time stamp order with green color circle for unseen notifications.
when we click on any unseen notification , open new pop up which shows title and whole content and with ok button.
when notification is seen then reduce the count on the bell icon.