Adding newly imported users to several groups - powershell

Question

I am new to Powershell... I have also done a lot of "looking", to see if I could find a resolution, before posting this question. While I have found several "close" answers (a good example is: Adding newly created users to pre-existing groups), I have not found one which meets our needs. The issue is wanting to add the new user to several groups at once, and I cannot get the syntax right. I have tried:
Add-ADGroupMember -Identity $_.Group -Members $_.SamAccountName
This works, but only adds one group. I have tried:
Add-ADGroupMember -Identity 'Group1','Group2','Group3' $_.SamAccountName
And
Add-ADGroupMember -Identity "Group1","Group2","Group3" -Members $_.SamAccountName
None of which worked. I have tried $(group1,group2,group3)... I just need help getting the right wording. The script in the picture works just fine, but only gives me 1 group. Please help me figure out how to add multiple groups. (I tried to copy/paste the actual script into this question, and it formats very oddly.
An image of the code which works fine

Answer 1

I'm not terribly familiar with that command, but have you tried either creating a text document with each group name separated by either a , or each new group has its own line?
That way at the start of the script you can say:
$groups = get-content path.txt
and run a foreach loop, like:
foreach ($group in $groups){
Add-ADGroupMember -Identity $group -Members $.SamAccountName}
or if you'd like to input the groups manually, instead of get-content, you can add this at the start of your sctipt:
[CmdletBinding()]
param (
[Parameter(Mandatory=$true,HelpMessage='Enter a list of group names seperated by a
comma, no spaces')]
[string]$List
)

Answer 2

So, your code (the one provided on the screenshot) is fine. It works because you're providing only one group to the -Identity parameter.
Taken from MS Docs:
-Identity
Specifies an Active Directory group object by providing one of the following values.
The identifier in parentheses is the Lightweight Directory Access Protocol (LDAP) display name for the attribute.
The acceptable values for this parameter are:
A distinguished name
A GUID (objectGUID)
A security identifier (objectSid)
A Security Account Manager account name (sAMAccountName)
If you were to add the newly created AD User to multiple groups, you can loop through the Groups and add the user to each one of them.
# In this example you will need to capture $_.sAMAccountName in a variable
$usersAMAccountName = $_.sAMAccountName
"Group1,Group2,Group3".split(',')|foreach{
Add-ADGroupMember -Identity $_ -Members $usersAMAccountName
}
# This is another option
foreach($group in "Group1","Group2","Group3")
{
Add-ADGroupMember -Identity $group -Members $_.samAccountName
}
I would recommend Splatting for New AD User creation, which is something used on the answer provided on the SO link Adding newly created users to pre-existing groups
Specifically this is perfect in my opinion:
try
{
$newADUser = New-ADUser #newUserProperties -PassThru
Add-ADGroupMember -Identity $_.Group -Members $newADUser.SamAccountName
}
catch
{
Write-Warning "Could not create $($newUserProperties.samaccountname)"
}