To watch TV channels on your computer, you need a TV tuner card or an external USB TV tuner dongle. Plug an external TV tuner into a USB port of your computer, and connect an antenna or cable TV cable to the connector at the other end of the dongle.
A pop-up window appears on your computer telling you that there is a new device if your USB TV tuner supports the plug-and-play feature; otherwise, restart your computer. Install the driver and software that come with the device. Once installed, you can use the software to scan for available TV channels and watch them on your computer.