source/StartMenu/Win10-LayoutModification_AVDClient.xml

<LayoutModificationTemplate
    Version="1"
    xmlns="http://schemas.microsoft.com/Start/2014/LayoutModification"
    xmlns:defaultlayout="http://schemas.microsoft.com/Start/2014/FullDefaultLayout"
    xmlns:start="http://schemas.microsoft.com/Start/2014/StartLayout"
    xmlns:taskbar="http://schemas.microsoft.com/Start/2014/TaskbarLayout"
>
  <LayoutOptions StartTileGroupCellWidth="6" />
  <DefaultLayoutOverride>
    <StartLayoutCollection>
      <defaultlayout:StartLayout GroupCellWidth="6" xmlns:defaultlayout="http://schemas.microsoft.com/Start/2014/FullDefaultLayout">
        <start:Group xmlns:start="http://schemas.microsoft.com/Start/2014/StartLayout">
          <start:DesktopApplicationTile Size="2x2" Column="0" Row="0" DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Azure Virtual Desktop.lnk" />
        </start:Group>
      </defaultlayout:StartLayout>
    </StartLayoutCollection>
  </DefaultLayoutOverride>
  <CustomTaskbarLayoutCollection PinListPlacement="Replace">
    <defaultlayout:TaskbarLayout>
      <taskbar:TaskbarPinList>
	      <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Azure Virtual Desktop.lnk" />
      </taskbar:TaskbarPinList>
    </defaultlayout:TaskbarLayout>
  </CustomTaskbarLayoutCollection>
</LayoutModificationTemplate>