I went to have a look at how my setup is, er, setup, only to discover that I had forgotten the router password. So, after pressing the reset button on my DG384, I can tell you the steps I went through to set up the wireless security.
Point your browser to 192.168.0.1 (presuming you haven't changed that) and select the wireless setting.
Click the WPA-PSK (Wi-Fi Protext Access Pre-Shared key), the screen refreshes so you can enter a code of your choice.
At this point your wireless connection drops.
If you are using the Netgear Smart Wizard software, go to the Network tab and scan.
Select the network.
Back on the Settings tab select Advanced and click the Advanced Security button.
Enter the same code that you input into your router.
You may then need to re-scan and select your network.
Hopefully that helps.
Regards
Stoney