Scroll Thumb into direct place of ScrollBar WPF - wpf

Question

How to choose position in ScrollBar and move there Thumb? And what i should add to shift Thumb on one position of mine information at ScrollBar?
<Style x:Key="ScrollBarPageButtonStyle" TargetType="{x:Type RepeatButton}">
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="Focusable" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type RepeatButton}">
<Border BorderBrush="Transparent"></Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="ScrollBarThumbStyle" TargetType="{x:Type Thumb}">
<Setter Property="IsTabStop" Value="False"/>
<Setter Property="Focusable" Value="False"/>
<Setter Property="Margin" Value="1,0,1,0" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Thumb}">
<Border CornerRadius="4" Width="10">
<Border.Background>
<RadialGradientBrush>
<GradientStop Color="#FF322E2E"/>
<GradientStop Color="#FF363232" Offset="0.385"/>
<GradientStop Color="#FF2B2626" Offset="1"/>
</RadialGradientBrush>
</Border.Background>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="VerticalScrollBar" TargetType="{x:Type ScrollBar}">
<Border CornerRadius="5" Width="14" >
<Border.Background>
<RadialGradientBrush>
<GradientStop Color="#FF645B5B" Offset="0.923"/>
<GradientStop Color="#FF685F5F" Offset="0"/>
</RadialGradientBrush>
</Border.Background>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Track Name="PART_Track" Grid.Row="1"
IsDirectionReversed="True" ViewportSize="28" >
<Track.DecreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageUpCommand" Style="{StaticResource ScrollBarPageButtonStyle}">
</RepeatButton>
</Track.DecreaseRepeatButton>
<Track.Thumb>
<Thumb Style="{StaticResource ScrollBarThumbStyle}">
</Thumb>
</Track.Thumb>
<Track.IncreaseRepeatButton>
<RepeatButton Command="ScrollBar.PageDownCommand" Style="{StaticResource ScrollBarPageButtonStyle}">
</RepeatButton>
</Track.IncreaseRepeatButton>
</Track>
</Grid>
</Border>
</ControlTemplate>
<Style TargetType="{x:Type ScrollBar}">
<Setter Property="Template" Value="{StaticResource VerticalScrollBar}"/>
</Style>