I have added two new standard users to the system and I open two terminals, one I am logged in with my credentials and the other I am signed in as one of the new users.

We try to view a root owned directory and see the new user does not have root privileges.

The new login ID is made a privileged user by adding the userID in the sudoers file. And we show the new user ID can now get into the root directory

To make the second userID a privileged user we add that userID to the group sudo (Note on RHEL system they use the wheel group in place of the sudo group)