Creating Dropdown Menu in SharePoint Online – using PowerShell

I need some assistance with my PowerShell script. Currently I am able to add a drop down menu to my page, but I am trying to add some subfolders to “Support Center”. Also if I wanted to add my drop down to multiple $SiteURL, how do I create it to loop for that?

I have pasted my current code below that adds a drop down in one site URL.

Thank you for any assistance!

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions16ISAPIMicrosoft.SharePoint.Client.dll"
Add-Type -Path "C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions16ISAPIMicrosoft.SharePoint.Client.Runtime.dll"
 
#Add new Link in Top Navigation
Function Add-SPOTopNavigationLink()
{
    Param(
        (String)$SiteURL,
        (parameter(Mandatory=$false))(String)$ParentNodeTitle,
        (String)$Title,
        (String)$URL
    )

    $user = "user"
    $file = "location"
    #Create new credential object and get encrypted password from file 
    $cred = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $user, (Get-Content $file | ConvertTo-SecureString)
    $Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
 
    #Setup the context
    $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
    $Ctx.Credentials = $Credentials
 
    #Get the Top Navigation of the web
    $TopNavigationBar = $Ctx.Web.Navigation.TopNavigationBar
    $Ctx.load($TopNavigationBar)
    $Ctx.ExecuteQuery()
 
    #Populate New node data
    $NavigationNode = New-Object Microsoft.SharePoint.Client.NavigationNodeCreationInformation 
    $NavigationNode.Title = $Title
    $NavigationNode.Url = $URL
    $NavigationNode.AsLastNode = $true
 
    #Get the Parent Node
    $ParentNode = $TopNavigationBar | Where-Object {$_.Title -eq $ParentNodeTitle}
     
    #Add New node to the navigation
    If($ParentNode -eq $null)
    {
        #Check if the Link with Title exists already
        $Node = $TopNavigationBar | Where-Object {$_.Title -eq $Title}
        If($Node -eq $Null)
        { 
            #Add Link to Root node of the Navigation
            $Ctx.Load($TopNavigationBar.Add($NavigationNode))
            $Ctx.ExecuteQuery()
            Write-Host -f Green "New Link '$Title' Added to the Navigation Root!"
        }
        Else
        {
            Write-Host -f Yellow "Navigation Link '$Title' Already Exists in Root!"
        }
    }
    else
    {
        #Get the Parent Node
        $Ctx.Load($ParentNode)
        $Ctx.Load($ParentNode.Children)
        $Ctx.ExecuteQuery()
  
        #Check if the Link with given title exists
        $Node = $ParentNode.Children | Where-Object {$_.Title -eq $Title}
        If($Node -eq $Null)
        { 
            #Add Link to Parent Node
            $Ctx.Load($ParentNode.Children.Add($NavigationNode))
            $Ctx.ExecuteQuery()
            Write-Host -f Green "New Navigation Link '$Title' Added to the Parent '$ParentNodeTitle'!"
        }
        Else
        {
            Write-Host -f Yellow "Navigation Link '$Title' Already Exists in Parnet Node '$ParentNodeTitle'!"
        }
    }
}
  
#Config Parameters
$SiteURL="https://test.sharepoint.com/sites/TestTopLinkBar"
 
#Call the function to Add a New Link in Root of the navigation
Add-SPOTopNavigationLink -SiteURL $SiteURL -Title "TESTING - HOME" -URL "https://yahoo.com"
 
#Call the function to Add a link in "Support Center" node of the navigation
Add-SPOTopNavigationLink -SiteURL $SiteURL -ParentNodeTitle "TESTING - HOME" -Title "Support Center" -URL "https://google.com"

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