Smart TVs give you direct access to the Internet, which means you can do all sorts of web-related things: watch YouTube videos, stream Netflix movies, explore AmazonPrime or another media-streaming account, Skype, listen to customized music with services such as Pandora, and post and look at photos on Facebook. They often have additional apps that let you easily check the weather or sports scores.
Just plug it in as you would a regular TV, then walk through the manufacturer's instructions for getting it connected to your home's Wi-Fi. It shouldn't be much more difficult than connecting your laptop or tablet to a new Wi-Fi network.
It looks like a regular TV, but it's wirelessly connected to the Internet. You can conveniently access all its features through its standard remote.
If you don't have a smart TV, but your standard TV has an HDMI port (as most newer models do) you can add smart features with streaming devices. Popular devices include Roku, Google Chromecast, AppleTV, and Amazon Fire TV Stick -- all options that are under $100. The apps and features they offer vary, so research before buying to find the device that offers you the functions you're most excited about in a smart TV.