<Grid Background="LightBlue" ShowGridLines="True" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">

  <!-- Define four rows: -->
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto"/>
    <RowDefinition/>
    <RowDefinition/>
    <RowDefinition/>
  </Grid.RowDefinitions>

  <!-- Define two columns: -->
  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="Auto"/>
    <ColumnDefinition/>
  </Grid.ColumnDefinitions>

  <!-- Arrange the children: -->
  <Label    Grid.Row="0" Grid.Column="0" Background="Blue" Foreground="White"
            HorizontalContentAlignment="Center"
            Grid.ColumnSpan="2">Strona startowa</Label>
  <GroupBox Grid.Row="1" Grid.Column="0" Background="White"
            Header="Zaczynamy">...</GroupBox>
  <GroupBox Grid.Row="2" Grid.Column="0" Background="White"
            Header="Niedawne">...</GroupBox>
  <GroupBox Grid.Row="3" Grid.Column="0" Background="White"
            Header="Opcje">...</GroupBox>
  <GroupBox Grid.Row="1" Grid.Column="1" Background="White"
            Header="Artykuły" Grid.RowSpan="3">
    <ListBox>
      <ListBoxItem>Artykuł #1</ListBoxItem>
      <ListBoxItem>Artykuł #2</ListBoxItem>
      <ListBoxItem>Artykuł #3</ListBoxItem>
      <ListBoxItem>Artykuł #4</ListBoxItem>
    </ListBox>
  </GroupBox>
</Grid>