I bought an Airport Extreme
Got that
but set up is not working (amber light blinks)
Got that
wifi not working
Not sure if this means.....
You can "see" the wireless signal, but not connect
or
You can connect to the wireless signal, but cannot get an Internet connection
or
You cannot even "see" the wireless signal at all?
Can you clarify on that?
Internet works through a wired connection to the back of the Airport Express
So, does this mean that you are connecting the AirPort Extreme to an AirPort Express that is already set up and working?
Do you want configure the AirPort Extreme to continue to connect to the AirPort Express using a wired Ethernet cable connection?
If not, are you saying that you want the AirPort Extreme to connect to the AirPort Express using a wireless connection?
To offer suggestions, we would need to know what operation system you are using on your Mac to set things up. Can you provide that information?