Wifi no connected

Hello,
#
Good Day!! i am using samsung gt-5233w, it was failed bec its asking the authentication key?

but where to enter the authentication key,. i open the DETAILS to enter it but i cannot find..

These are the settings of my network:

Connection: Infrastructure
Security Type: WPA
Channel: 11
AP MAC: 00-1A-7094-4B-76
Device MAC:00-21-E8-3F-50-43
IP ADDRESS : not connected

WHAT TO DO???

thanks a lot.