D-link n300 lock security

[Bob the Novice]

Hello,
Have a two year old Mac using OSX 10.6.8 connected to a D-Link N300 DIR-615 for wireless use with iPad, but now concerned about wireless security. How do I go about securing the D-Link?

 

[Guest]

http://www.tomshardware.com/forum/31382-43-find-security-password-wireless-router