can't connect to wifi

[Android Question]

i bought it yesterday after i have a contract with Fido. I go back to my apartment and tried to used my wifi to start download software but it showed "internet is not available via selected WI-FI AP", what should i do??
my phone model is galaxy s3

 

[AndyOpie150]

Welcome to Android Forums.

Go to menu/settings/Wireless and Networks. Turn WiFi on then select the WiFi settings. Select your Wireless network and enter your passcode when prompted.
If still having a problem:
Turn router off. Unplug from power.
Delete network on phone. Turn phone off. Pull battery. Hold power button for 30 seconds.
Wait 5 minutes
Plug router back into power. Turn on and let fully reboot.
Turn phone on.
When fully rebooted, try signing into network.

For more phone specific info and support go here: Samsung Galaxy S3 - Android Forums