Hello here is the guide:
Plug in your extender. ...
Connect your computer or mobile device to the extender's WiFi network. ...
Launch a web browser and enter mywifiext.net. ...
Click or tap NEW EXTENDER SETUP. ...
Choose your extender's admin credentials. ...
Select and answer two security questions from the drop-down menus. ...
Click or tap NEXT.
To know more click here:
Netgear Wifi Extender Setup