While connecting to the range extender for the first time, a user has to make sure that he knows the correct default Wireless credentials of the extender. You can fetch the default Wireless settings from the back of your device through its product label. Once you are connected to the extender's network wirelessly, you just need to type extender.linksys.com or 192.168.1.1 on the address bar to interact with its interface.
https://linksys-extendersetup.net