table level permissions

Is there a tutorial on the best practices for table level permission settings?

From what I understand in the help section it is as easy as adding a user group (UG) and naming is whatever I want then assigning the table permissions on them. e.g.

admin > everything (this is the default I think)
UG_manager > give access to everything buy users
UG_employee > give access only to tables that they need
UG_guest > give read only access to a specific table

Is it really that simple or am I over thinking it.

the last CMS I used assigned numerical values not alphabeticals

TIA