Editing Taskbar Layout modification with Powershell

I am preparing Windows 11 deployment for my company and I found an XML that I can use for setting up customised icons pinned to taskbar .

I want to edit XML document during install process - let's say - if computer has Office installed I want Word and Outlook icons pinned to taskbar.

This is the XML:

 <?xml version="1.0" encoding="utf-8"?>
<LayoutModificationTemplate
	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"
    Version="1">
	<CustomTaskbarLayoutCollection PinListPlacement="Replace">
		<defaultlayout:TaskbarLayout>
			<taskbar:TaskbarPinList>
				<taskbar:DesktopApp DesktopApplicationID="Microsoft.Windows.Explorer"/>
				<taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Google Chrome.lnk"/>
				<taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Firefox.lnk" />
				<taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Microsoft Edge.lnk" />
			</taskbar:TaskbarPinList>
		</defaultlayout:TaskbarLayout>
	</CustomTaskbarLayoutCollection>
</LayoutModificationTemplate> 

How can I add a line

				<taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Outlook.lnk" />

to this XML after first 4 icons?

I found out how to open XML in Powershell, but I am lost how to add line in the correct part of XML.

Thank you for your help!

The below should do the trick, you will just need to add if your IF statements or whatever to decide what you want to add. Currently it only adds the one example you provided for Outlook, but you can define as many NewChilds as you want, and import them in a foreach:

                # Define the XML content
            [xml]$xmlDocument = '<?xml version="1.0" encoding="utf-8"?>
            <LayoutModificationTemplate
                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"
                Version="1">
                <CustomTaskbarLayoutCollection PinListPlacement="Replace">
                    <defaultlayout:TaskbarLayout>
                        <taskbar:TaskbarPinList>
                            <taskbar:DesktopApp DesktopApplicationID="Microsoft.Windows.Explorer"/>
                            <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Google Chrome.lnk"/>
                            <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Firefox.lnk" />
                            <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Microsoft Edge.lnk" />
                        </taskbar:TaskbarPinList>
                    </defaultlayout:TaskbarLayout>
                </CustomTaskbarLayoutCollection>
            </LayoutModificationTemplate>'

            # Define the child to be added
            [xml]$NewChild = @"
            <Grid xmlns:taskbar="http://schemas.microsoft.com/Start/2014/TaskbarLayout">
                <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Outlook.lnk" />
            </Grid>
            "@

            # Create a namespace manager and Insert the new child after the last one under TaskbarPinList
            # Namespace is required due to none default namespace "taskbar"
            $nsManager = New-Object System.Xml.XmlNamespaceManager($xmlDocument.NameTable)
            $nsManager.AddNamespace("taskbar", "http://schemas.microsoft.com/Start/2014/TaskbarLayout")
            #Import the new child into the XML doc to create a node
            $targetNode = $xmlDocument.SelectSingleNode("//taskbar:TaskbarPinList", $nsManager)
            #Insert the node where we want it
            $newNode = $xmlDocument.ImportNode($NewChild.Grid.SelectSingleNode('taskbar:DesktopApp', $nsManager),$true)
            [VOID]$targetNode.InsertAfter($newNode, $targetNode.LastChild)

            #Save the XML where ever you require
            $xmlDocument.Save('FILE PATH OR VARIABLE CONTAINING A PATH HERE')