Connection tp-link extender TL-WA850RE

Hi, I have a problem with the tp-link TL-WA850RE connection. I can not log in to the site where I need to configure. I am asking for an explanation, as far as a pathological method is concerned, because I am a woman who generally does not sit in this topic on a daily basis.

Is the device new or used? Did you reset your factory settings? In the first place you connect to the wireless network of the amplifier or wired.
http://www.tp-link.com/us/faq-698.html

The device is new. First, I connected wirelessly but it did not catch the network, I connected my laptop cable for the second time and I was unable to log into the configuration page.

What does it mean that it did not catch the network? Must connect when you enter the appropriate security (password should be on the case).
After connecting, you log in via the http://tplinkrepeater.net domain address or the IP address http://192.168.0.254

Ok, thank you for your help