Difference in CMS pages and categories permission in the top and CMS

[J.Sahu]

I have a general question what is the difference between the CMS pages, CMS categories and  CMS

When I tried to create a new administrator in the permission list there are different menus. In the menu list CMS is there but there are two menus CMS page and CMS categories. I've tried to change the values but nothing is happening to the CMS block. Can someone tell me if we change the permissions on the CMS pages and CMS categories where does the impact is reflect ? and yes what is the home and catalog menu ? I changed the permission value but nothing is happening.