I have a router how i can access internet

the device you have is not a router it is an Access Point which needs to be connected to router with internet.

http://www.tp-link.com/en/products/details/?model=TL-WA...

You need to get a modem and a router and set up a wireless network , then you can use this device to extend the range of the network. By itself the device that you have is not going to do you any good and you cannot establish a wireless network with it.