Hi Julie,
Check out this link:
https://support.vizio.com/s/article/How-to-add-an-App-to-your-VIZIO-Smart-TV?language=en_US
You can find out how to add new apps, and also how to use ChromeCast or AirPlay to use your phone to browse and send shows to your TV.
The soundbar will be a little trickier. You can look up the model number on YouTube or the manufactures website for configuration help. Otherwise, you might have Best Buy come back out to resolve the issue in person.