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Help/FAQHow do I pick the moderators?
If you are are the group 'owner' you can select moderators and grant special permissions (like approving new members, editing or deleting topics, etc).
Go to Members, and find the person you want to be a moderator - selecting who is up to you: base it on personal knowledge, or how they have behaved on the group, whatever. As a group owner, you can change or remove these permissions later.