I'm very beginning to the Drupal. I created on role from my admin part, I need to access the roles with some permissions like i listed below. 

My concept is ticket raising system in various categories. As an admin I assign some ticket to some roles(user), now how to give permissions to assign roles(user)? 

Also, the assigned user have to do action what they have to do, but they don't have permission to access admin part. How to give permission to the user to do the reply?