You plug it into a socket that's within range of the wifi from your router, and in the direction you want there to be better coverage. You then connect to the extender via the default wifi name, and log into it (the manual will tell you the link). Then, follow the instructions for it to connect to your router, and it will use the same details to extend it. The wifi name might be slightly different but the password will be the same as your router wifi.
