Seeded Role Privileges and their included functionality

Summary

Looking for a simple-to-understand guide to roles and what functionality they permit

Content

Hello,

I am an HR user who until now has been responsible for design and testing.  I now am becoming responsible for the security of roles and ensuring users have the minimum access required to perform their duties - this includes all users, from Employees to the Configuration Team.

I am looking for a decent place to start in terms of answering questions such as:

"If I allocate the role of Application Implementation Consultant to a user, what exactly does this enable the user to do in the system?"