Outlook for Mac, 365, Contact List

I have Outlook for Mac, new Outlook, with a Microsoft 365 custom domain account.

I wasn't to create a Contact List.  I have some addresses that I want to add that are not in my account Contacts.

How do I add these names with the the name so when it is add to the list shows as follows:

Len Levin

xxxxx.domain.com

Thanks

Len