Using Relative Layout with an alternate method of calling the class.

RelativeLayout.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Xamarin.Forms;
namespace App6
{
    public class App : Application
    {
        public App()
        {
            MainPage = new RelativeLayoutExample();
        }
        }
    public class RelativeLayoutExample : ContentPage
        {   
            public RelativeLayoutExample()
            {
                this.Padding = new Thickness(10, Device.OnPlatform(20, 0, 0), 10, 5);

                Label heading = new Label {Text = "RelativeLayout Example",TextColor = Color.Red,};

                Label relativelyPositioned = new Label{Text = "Positioned relative to my parent."};

                RelativeLayout relativeLayout = new RelativeLayout();

                relativeLayout.Children.Add(heading, Constraint.RelativeToParent((parent) => {
                    return 0;
                }));

                relativeLayout.Children.Add(relativelyPositioned,
                    Constraint.RelativeToParent((parent) => {
                        return parent.Width / 3;
                    }),
                    Constraint.RelativeToParent((parent) => {
                        return parent.Height / 2;
                    }));
                this.Content = relativeLayout;
            }
        }
}

Relative Layout screenshot