how to add WPA2 PASSWORD
my airport express broke so i had to dig out my old one. when i click the little radar bar it shows my network but no lock next to it meaning anyone can use my wifi. its been so long that i forgot what to click so i could add a wpa2 or any sort of password. when i did this on my old one a little picture of a lock appeared telling me i had security. when i got to system preferences it shows my wifi address but under the word security it says 'NONE'
can anyone remind me what i have to do so i can add either a wpa2 or just any kind of security so that only i can access my wifi?
MacBook Pro, Mac OS X (10.7.5)