Here is a YouTube computer tutorial about Five Steps to Secure Linux, and is part of a growing collection of videos I have found which should be useful to you for hardening your linux to make it intruder resistant. There are thousands of YouTube computer tutorials out there, but this is a good one when you need hardening your linux to make it intruder resistant.
This tutorial, "Five Steps to Secure Linux" is a free tutorial you can watch, which will help you understand how to get better performance, usability, and an overall better experience using your laptop or desktop computer.