connecting to a nonsmart tv

You can obtain a streaming device that outputs a signal that your TV can accept.  If your TV has an HDMI input, there are plenty of such devices and if it only will accept component or composite, your choices drop considerably.  Amazon makes various FireTV Sticks and the FIreTV Cube.  Google has the Chromecast. Apple has AppleTV.  There is also Roku and some lesser no-named brands. 

All of these will connect to the Internet via Wi-Fi and provide a signal for your TV to display.

HOWEVER, you will need to figure out how you are going to obtain the programming you wish to watch over the Internet.  It is not as simple as having a dial and a list of channel numbers to scroll through.  There are free services, there are services bundled with other things (e.g. Amazon Prime Video comes with Amazon Prime, some wireless plans come with some video packages, etc).

Thank you, I tried the Roku starter, but it doesn’t work on the TV. I think my TV might be too old. However, when I had Xfinity they had a special that you connected to the TV and all the channels movie channels and everything would work so I was just wondering if AT&T had the same kind of box.

Xfinity sells both Internet and a TV service, so you're talking about their TV service which you may have had as a package deal.

AT&T has a legacy TV service called U-verse TV which they no longer sell, so let's ignore that.

AT&T owns a majority stake in DIRECTV who has a service called "DIRECTV INTERNET" where they would provide a set top.  However, I don't know if that box has anything other than an HDMI output just like the Roku.  If you want more information on that, try https://forums.directv.com 

Thank you very much

@pfountain 

Roku, Firestick, etc. are just a streaming device that connects to your TV by HDMI. If an older TV than you may need an adapter to component or A/V (red/white/yellow plugs).

There is no TV too old to use those devices. Simply the older it is you need an adapter. Remember you are not connecting Internet (WiFi or otherwise) to the TV itself. You connect the streaming device, it just sends picture to the TV.

got cha thanks will try that

Please explain what problem was encountered using Roku.  This device should work fine.