You need to add and map credentials under Configuration\Scanning Setup\Scanning Credentials. You cannot submit or map credentials through the New Asset option in the Assets menu, if this is what you're asking. Refer to
this knowledge base article for more information. You can map a credential to a domain/workgroup, an IP range, an individual Windows computer or
an individual IP address.
In Lansweeper 6.0 you will be able to import credentials from a CSV file as well, but we don't have a release date for this update yet.