Google 4 Manual Book page 167

TIP: To extend the life of your battery
between charges, turn off Wi­Fi when
you're not using it. You can also set
your phone to disconnect automati­
cally from Wi­Fi networks when it's
sleeping.
Add a Wi-Fi network
You can add a Wi­Fi network so that your
phone will remember it, along with any secu­
rity credentials, and connect to it automati­
cally when it's in range. You must also add a
Wi­Fi network if the network does not broad­
cast its name (SSID), or to add a Wi­Fi net­
work when you are out of range.
To join a secured network, you first need to
learn security details from the network's
administrator.
WIRELESS & NETWORK SETTINGS 158