How to use :group command?

[Artur Skonecki]

I am sending mail once again, because alpine setup is probably causing
my mail to be filtered along the way.

Hi,
I keep thinking how to get workspaces in screen without nested
sessions and groups seem interesting because :windowlist has a "toggle
group nesting" command. But I am having trouble with instructions in
documentation.

Could someone explain how to create groups and administer them?

Thanks

--
Artur Skonecki
http://adb.cba.pl