To do the Linksys wifi extender setup, you need login credentials such as user ID and network key. If you don’t know the Linksys Extender login credentials, check the product label on your Linksys WiFi extender device. There will most likely be the user ID and password printed on it. If you do not find it, check the manual as well. If you are unable to find the Linksys extender login credentials in the manual as well, simply type in the “admin” in both the user ID and password blanks.