How to get unassigned phone numbers from Skype For Business powershell module

Has anyone ever done something like this in powershell? I’m automating new user creation and have to set up their skype for business accounts. Here’s what I have so far:

<# set up skype for business #> Enable-CsUser -Identity $FULLNAME ` -RegistrarPool REDACTED -SipAddress $SIP Set-CsUser $FULLNAME ` -EnterpriseVoiceEnabled $true ` -ExchangeArchivingPolicy Uninitialized ` -LineURI $PHONENUMBER # only for driver manager/managers Grant-CsConferencingPolicy $FULLNAME ` -PolicyName $ConferencingPolicy Grant-CsExternalAccessPolicy -identity $FULLNAME ` -PolicyName 'Allow external access' 

All I have left is the to assign the LineURI, and I can’t seem to find anything about how to do that. I did, however, find a script that does this, but it doesn’t seem like it’s specific to my needs. My question is this: how can I query Skype for Business in powershell to grab the first unassigned number and assign it as the LineURI? I have been using New-CSUnassignedNumber but cannot seem to make any headway.

Thanks!