check that there is no user in the local domains

I am a beginner, I must check that there are no users in the local domains of an OU. You should also see a message saying there are or not users with the user name and DL name.
Could someone help me finish this script? 
Here is what I have already done:


$OUList = Get-ADOrganizationalUnit -Filter "*"
foreach ($OU in $OUList) {
$comboBox1.Items.Add($OU) | Out-Null


$truc = $OUList.selecteditem


Get-ADGroup -Filter { Groupscope -eq 'DomainLocal' } -SearchBase $SelectVal |
ForEach-Object { $_ | Select-Object Name,DistinguishedName,@{
Name = 'Users'
Expression = {Get-ADGroupMember -Identity $_ | Where-Object {$_.ObjectClass -eq
'User'} | Select-Object -ExpandProperty Samaccountname}
$richTextBox1.Text = $combobox1.SelectedItem

#TODO: Place custom script here