If you need to connect to internet,try the following steps:
1. Go to"Setting"—"Wi-Fi" and choose an available Wi-Fi access point.
2. Go to "Setting"—"Cellular" and enable "Cellular Data"(your ISP may charge a fee for usage.)
If you have already connected to a Wi-Fi network:
Check if the Wi-Fi access point is connected to the internet, or whether the access point allows your device to access the internet.