New version - Groups feature (great!) - but how to configure access rights?

Hello!
I’ve just upgraded server to v2.1.18 and I see new feature: “Groups”. Unfortunately, documentation knows nothing about it (yet, I hope). So I must ask here:
How to configure access rights to give the user rights for groups (not for hosts)?
Thanks!

BTW: I asked to join translation team on transifex (server, pl), no answer so far…

Best regards!
WS