Here's a list of some resources you can check out next to help you get the most out of your newly installed and configured FortiGate.
The Best Practices document is a collection of guidelines to ensure the most secure and reliable operation of FortiGates in a customer environment. It is updated periodically as new issues are identified.
This document can be found at http://docs.fortinet.com/.
The Fortinet Cookbook
The Fortinet Cookbook contains a variety of step-by-step examples of how to integrate a FortiGate into your network and apply features such as security profiles, wireless networking, and VPN.
Using the Cookbook, you can go from idea to execution in simple steps, configuring a secure network for better productivity with reduced risk.
The Fortinet Cookbook can be found at http://cookbook.fortinet.com.
The Fortinet Video Library
The Fortinet Video Library contains video tutorials showing how to configure various Fortinet products, including FortiGates. Many FortiGate videos are based on recipes from the FortiGate Cookbook.
The FortiOS Handbook
The FortiOS Handbook is the complete guide to FortiOS, covering a variety of FortiGate configurations. The Handbook is available as a single complete document online. Handbook chapters are also available as standalone documents.
The FortiOS Handbook can be found at http://docs.fortinet.com/.