deeplogica
Hi
Do you want to allow a new user group to access your site admin ?
You need to apply changes in Joomla ACL for this, to allow access for new user group for admin access and other sections access.
Here is documentation for Joomla ACL helps you to know, how its works..
Please note : If you add an access for new user group, try the login yourself, since admin side is main part to operate site.