Create users and access

Hi.

I need to create, add access rights, and then add the user from powershell, but i can't figure out how to ADD the user.

I use:

Create user: New-NAVServerUser -WindowsAccount milestone\mskadmin -ServerInstance milestoneus2013

Add access rights: New-NAVServerUserPermissionSet milestoneus2013 -WindowsAccount milestone\mskadmin -PermissionSetId SUPER

But what do i do to ADD the user?

And, another thing... i got a database backup every night from a cloud service provider, but my account in the cloud is a cloud domain user, so how to i create a user in nav, when i has restored the database "at home" ?

/

David