To enable tethering on your Android mobile, please follow the steps below:
1. Unlock the phone and click on 'All Applications'.
2. Navigate to and click on 'Settings'.
3. Under Wireless & Networks > More... click on 'Tethering & Portable Hotspot'
If you want to tether over Wi-Fi please ensure you click the 'Portable Wi-Fi Hotspot'.
Alternatively you can click on 'USB tethering' if you want to use the USB cable.
Note: If you tether over Wi-Fi, ensure you click on 'Configure Wi-Fi hotspot' to configure your network SSID and add/edit your password.