Hi, you need to make sure your router is working first, then follow this instruction to set the extender up via web interface page. http://www.tp-link.com/en/faq-930.html

I am having the same problem on my MacBook Pro. The router works just fine for every other device in the house and the laptop connects to my Apple router without issue. I have also downloaded the firmware for that is supposed to address the problem and get the following message. If this issue is not resolved in the next few days, I will have to return the router to the retailer.

I think you can call the tech support hotline to let them guide you throught