In the Administration interface
go to WIRELESS -> LOCAL WIRELESS tab.
Securing Local Wireless Networks
A
.
Enter a name for your wireless network in the SSID field
B
.
Enable security for wireless network
C
.
Enter a passphrase in the WPA2 Key field
D
.
Click on the “Save” button
The same way you can manage SSID and
Security for Local 5GHz and guest wireless
interfaces