Download Xfinity App On Vizio Smart Tv. Or press the v key or home key near the center of your remote. This is so because it is not an official app on vizio smart tv.
When asked, register your device and sign in with your xfinity credentials. Build your own list of favorite apps. For now, you have to have sams/lg or go for the amazon stick or roku to use xfinity stream app.
On those, vizio offers a native vizio peacock app for their smartcast platform, as well as the ability to use google cast and airplay 2 (on supported devices).
To access applications on your smartcast tv, press the input button and choose the 'smartcast' input. Press the smart hub button on your smart control remote to go to the samsung home screen. Scroll to and select apps. Or press the v key or home key near the center of your remote.