Nagios Advice

Greetings all. I am finishing a Debian install, default, though I will be using XFCE. I am going to install Nagios for testing/learning purposes. What I am after is bandwidth monitoring (at least total bandwidth up/down from a server. Type of traffic a happy plus but not required). I have limited time to learn this atm, which makes it even more difficult. Anyone have some good links to how-to’s, or practical experience with nagios?