Pretty simple. Here's the text I send leader volunteers.
Thank you for volunteering to serve as group leader. You will share the responsibilities of the group moderation with your co-leader. Should your co-leader leave the group for any reason you will need to find another group leader to take her place.
As a leader you would keep an eye on the posts and behavior of members to make sure things stay nice. If you have a problem with a member that cannot be resolved directly you have the ability to remove that member from the group. You can also take on the role of initiating discussions to keep things lively. Again, this need not be a focused task but just a bit of encouragement here and there to get discussions going, especially when your group is brand new and whenever you see activity is slow.
We may also work with you to create contests and swaps to increase participation and help make the group a fun place to be a member. :)
Another role you serve is to invite others to join. It need not be a focused task but rather as you come across members around the forums you think might be interested in joining you can let them know about the group.
Once you join the group I will set you as group leader. Please select an image to represent the group and place it on your group landing page.
if you have any questions or problems you can contact me or AdinaL for assistance.
All the best and good luck with your group!