usually in browser, type in
192.168.0.1
or
192.168.0.255
in modem/router or Router wireless settings, turn on SSID
SSID SETUP
Broadcast SSID "ON"
reboot modem, restart all pc's
If you have a separate router connected to modem, then you will need a user and password to most likely access it. Look in your router manual or look online.