Example of Bottom Tabs implementation in Xamarin.Forms to Android - http://julianocustodio.com/android-bottom-tabs

TabbedPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="BottomTabsDemo.Home"
             Title="Demo"
             BarBackgroundColor="#2196F3"
             BarTextColor="White"
             xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
             android:TabbedPage.ToolbarPlacement="Bottom"
             android:TabbedPage.BarItemColor="#66FFFFFF"
             android:TabbedPage.BarSelectedItemColor="White">

    <ContentPage Title="Home" Icon="home.png"/>
    <ContentPage Title="RSS" Icon="rss.png"/>
</TabbedPage>