MainPage.xaml

<Page
    ...
    xmlns:controls="using:Microsoft.UI.Xaml.Controls">

    <Grid
        Padding="12"
        Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
        RowSpacing="8">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />           
        </Grid.RowDefinitions>
        <TextBlock
            FontSize="20"
            Style="{ThemeResource HeaderTextBlockStyle}"
            Text="Conway's Game of Life"
            TextAlignment="Center" />
        <Grid
            Grid.Row="1"
            ColumnSpacing="8"
            RowSpacing="8"
            HorizontalAlignment="Left">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="Auto" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition Width="Auto" />
            </Grid.ColumnDefinitions>

            <Button
                HorizontalAlignment="Stretch"
                Click="{x:Bind StartNewGame}"
                Content="Start new game" />
            <Button
                Grid.Column="1"
                HorizontalAlignment="Stretch"
                Click="{x:Bind Clear}"
                Content="Clear" />
            <Button
                Grid.Column="2"
                Click="{x:Bind NextGeneration}"
                Content="Next generation" />
          
            <controls:NumberBox
                x:Name="BoardSizeNumberBox"                                   
                Maximum="50"
                Minimum="3"
                Header="Board size"
                SpinButtonPlacementMode="Inline"
                Value="10" />
            <ToggleSwitch
                x:Name="AutoPlayToggleSwitch"
                Grid.Row="1"
                Grid.Column="2"
                Header="Auto-play"
                Toggled="{x:Bind AutoPlayToggled}" />
        </Grid>

        <Border
            x:Name="GameCanvasContainer"
            Grid.Row="2"
            SizeChanged="{x:Bind LayoutGameBoard}">
            <Canvas x:Name="GameCanvas" />
        </Border>
    </Grid>
</Page>