Tethering is typically a device specific feature not necessarily limited to the carrier, although only certain carriers allow simultaneous voice and data (meaning if you don't have this capabilities your Internet connection will be shut down when you receive an incoming call).
As far as how to do it you should check the phone's manual I'm not sure on that model although it's new enough that you should have the capabilities. Typically you would plug something into your phone (most likely the port you plug into in order to charge the phone) with a USB connection to your computer. I'm not sure how different carriers handle this from a pricing perspective, but some may charge you for this as you would most likely transmit much more data while using a laptop vs surfing the web on your phone. I would suggest you stop into your local store/mall kiosk and have them help you with it
