Part 1 Complete code (Windows Store apps using C#/VB and XAML)

<Application
    x:Class="HelloWorld.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HelloWorld"
    RequestedTheme="Light">

    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <!-- 
                    Styles that define common aspects of the platform look and feel
                    Required by Visual Studio project and item templates
                 -->
                <ResourceDictionary Source="Common/StandardStyles.xaml"/>
            </ResourceDictionary.MergedDictionaries>
            <Style x:Key="BigGreenTextStyle" TargetType="TextBlock">
                <Setter Property="Foreground" Value="Green"/>
                <Setter Property="FontSize" Value="36"/>
                <Setter Property="FontFamily" Value="{StaticResource ContentControlThemeFontFamily}"/>
                <Setter Property="TextTrimming" Value="WordEllipsis"/>
                <Setter Property="TextWrapping" Value="Wrap"/>
                <Setter Property="Typography.StylisticSet20" Value="True"/>
                <Setter Property="Typography.DiscretionaryLigatures" Value="True"/>
                <Setter Property="Typography.CaseSensitiveForms" Value="True"/>
            </Style>

        </ResourceDictionary>
    </Application.Resources>
</Application>

<common:LayoutAwarePage
    x:Name="pageRoot"
    x:Class="HelloWorld.MainPage"
    DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HelloWorld"
    xmlns:common="using:HelloWorld.Common"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Page.Resources>
        <!-- TODO: Delete this line if the key AppName is declared in App.xaml -->
        <x:String x:Key="AppName">Hello, world!</x:String>
    </Page.Resources>

    <!--
        This grid acts as a root panel for the page that defines two rows:
        * Row 0 contains the back button and page title
        * Row 1 contains the rest of the page layout
    -->
    <Grid Style="{StaticResource LayoutRootStyle}">
        <Grid.RowDefinitions>
            <RowDefinition Height="140"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!-- Back button and page title -->
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <Button x:Name="backButton" Click="GoBack" 
                    IsEnabled="{Binding Frame.CanGoBack, ElementName=pageRoot}" 
                    Style="{StaticResource BackButtonStyle}"/>
            <TextBlock x:Name="pageTitle" Grid.Column="1" 
                       Text="{StaticResource AppName}" 
                       Style="{StaticResource PageHeaderTextStyle}"/>
        </Grid>
        
        <!-- Controls added in PART 1. -->
        <StackPanel Grid.Row="1" Margin="120,30,0,0">
            <TextBlock Text="What's your name?" Style="{StaticResource BasicTextStyle}"/>
            <StackPanel Orientation="Horizontal" Margin="0,20,0,20">
                <TextBox x:Name="nameInput" Width="300" HorizontalAlignment="Left"/>
                <Button Content="Say &quot;Hello&quot;" Click="Button_Click"/>
            </StackPanel>
            <TextBlock x:Name="greetingOutput" Style="{StaticResource BigGreenTextStyle}"/>
        </StackPanel>
        <!-- End -->

        <VisualStateManager.VisualStateGroups>

            <!-- Visual states reflect the application's view state -->
            <VisualStateGroup x:Name="ApplicationViewStates">
                <VisualState x:Name="FullScreenLandscape"/>
                <VisualState x:Name="Filled"/>

                <!-- The entire page respects the narrower 100-pixel margin convention for portrait -->
                <VisualState x:Name="FullScreenPortrait">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" 
                                                       Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" 
                                                    Value="{StaticResource PortraitBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>

                <!-- The back button and title have different styles when snapped -->
                <VisualState x:Name="Snapped">
                    <Storyboard>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="backButton" 
                                                       Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" 
                                                    Value="{StaticResource SnappedBackButtonStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="pageTitle" 
                                                       Storyboard.TargetProperty="Style">
                            <DiscreteObjectKeyFrame KeyTime="0" 
                                                    Value="{StaticResource SnappedPageHeaderTextStyle}"/>
                        </ObjectAnimationUsingKeyFrames>
                    </Storyboard>
                </VisualState>
            </VisualStateGroup>
        </VisualStateManager.VisualStateGroups>
    </Grid>
</common:LayoutAwarePage>

' The Basic Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234237

''' <summary>
''' A basic page that provides characteristics common to most applications.
''' </summary>
Public NotInheritable Class MainPage
    Inherits Common.LayoutAwarePage

        ''' <summary>
        ''' Populates the page with content passed during navigation.  Any saved state is also
        ''' provided when recreating a page from a prior session.
        ''' </summary>
        ''' <param name="navigationParameter">The parameter value passed to
        ''' <see cref="Frame.Navigate"/> when this page was initially requested.
        ''' </param>
        ''' <param name="pageState">A dictionary of state preserved by this page during an earlier
        ''' session.  This will be null the first time a page is visited.</param>
        Protected Overrides Sub LoadState(navigationParameter As Object, pageState As Dictionary(Of String, Object))

        End Sub

        ''' <summary>
        ''' Preserves state associated with this page in case the application is suspended or the
        ''' page is discarded from the navigation cache.  Values must conform to the serialization
        ''' requirements of <see cref="Common.SuspensionManager.SessionState"/>.
        ''' </summary>
        ''' <param name="pageState">An empty dictionary to be populated with serializable state.</param>
        Protected Overrides Sub SaveState(pageState As Dictionary(Of String, Object))

        End Sub

    Private Sub Button_Click(sender As Object, e As RoutedEventArgs)
        greetingOutput.Text = "Hello, " & nameInput.Text & "!"
    End Sub
End Class