Assigning permission and roles to users

Hi All,

I am configuring the "Quality Manager" project from RTC. In which 5 users are created and assigned the roles to every team mamber, but one default role is getting assigned automatically which we can't remove :(

The default role is having most of the permissions which we can modify from "Process Configuration" tab.

Let's see the scenario and problem.
1. I am creating a formal review process as follows for a test case.
2. "testmanager" should only the person eligible to modify the review process and "tester" can only read the reviewer and approver.
4. So I am removing the this permission from everyones(default) permission list and assigning to only "testmanager"
5. when I tried to add new approver as a "testmanager" user, I am not able to do it. It's read only for me also.

So, Is everyone(default) permission are overriding the individual permissions?.

pleae guide me.
Is anybody having administrative guide for this?

Regards,
Milind