Unfortunately, this is simply not possible.
These westinghouse tvs, even for their smart models, are very basic low end models and have very limited features.
There is no app store, and there is no possibility of adding additional apps for it. For that to happen westinghouse would have to publish a specific feature upgrade for this model, which will not happen, they do not add or expand features, and rarely even provide necessary updates to support their existing products.
One option would be to return the tv and purchase a different model. I would strongly urge you to consider this. These westinghouse tvs are some of the lowest quality sets on the market, they have extremely high failure rates and short service lives. You will be lucky if the tv lasts you a few years at best. For about $50 more you could buy a more reputable brand model that will have the features you want and will last far longer.
Alternately if you prefer to keep this one, you can expand its functionality by connecting an external streaming device such as a a roku or fire tv and get all the same functions and many more, with better performance and support.
If you would like some replacement recommendations for a different model, I can help with that.
My apologies for the news,