How to make custom info window in xamarin forms maps?

Question

I want to create a custom info window in my Xamarin forms map,How can I implement this.I am using xamarin.forms.map map plugin to create map. Please Help me I want a custom info window like this one

i make custom map and custom pin

public class CustomMap : Map
{
public List CustomPins { get; set; }
}

Custom Pin

public class CustomPin : Pin
 {
 public string ImageUrl { get; set; }
 public float rating { get; set; }
 }

Map page xaml.cs

public partial class MapPage : ContentPage
    {
        CustomPin pin;
        MapVM MapVM;
        public MapPage()
        {
            InitializeComponent();

            pin = new CustomPin
            {
                Type = PinType.Place,
                Position = new Position(37.79752, -122.40183),
                Label = "Xamarin San Francisco Office",
                Address = "394 Pacific Ave, San Francisco CA",
                Url = "http://xamarin.com/about/",
                rating = 3

            };
            var pin1 = new CustomPin
            {
                Type = PinType.Place,
                Position = new Position(38.79752, -124.40183),
                Label = "Xamarin San Francisco Office",
                Address = "395 Pacific Ave, San Francisco CA",
                Url = "http://xamarin.com/about/",
                rating=2

            };

            customMap.CustomPins = new List { pin, pin1 };
             customMap.Pins.Add(pin);
            customMap.Pins.Add(pin1);
            customMap.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(37.79752, -122.40183), Distance.FromMiles(1.0)));
        }
}

now i don't know about custom render class. please help me how i can define custom render class and how i assign the image value and rating values to display in info window..