The admin is one of the group members who has the power to manage all group members. He/she is appointed by the group owner, who is therefore responsible for managing his/her group’s admins.
The list of group admins is accessible from the group page in the Administrators tab.
To add a new administrator, click on the Add administrator button.
To remove an admin, tick the checkbox at the beginning of the line and then click on the Remove selected administrators button.