How can I add/move icloud contacts to a group? I see that iCloud can create groups. It appears that other than All Contacts, I only have another group, contacts-other that was created when I imported my addresses (I think via Outlook, which I no longer use).

How can I assign contacts to a group?
On iCloud.com, open Contacts.  Then, click on the ribbon with the people icon until the groups appear.  Now, hit the plus icon at the bottom, and name the new group.  Click back on "All Contacts".  Now, simply drag each contact that you want to move into the group.  If you want to select more than one at a time, just hold down the Command key (control key on Windows) and click on each one, then drag them all into the group.