Samsung Smart TV control

My dad got himself a Samsung Smart TV today and was asking how he can control it with his gHome, mostly to just turn it on and off. From what I’m reading SmartThings Extend is built into the TV, but that doesn’t give it the ability to turn the TV on and off, does it? Isn’t that just the SmartThings Hub (which he already has) built into the tv? I did find this SmartApp https://github.com/bradmb/smartthings-samsung-tv, which seems to do what I want it to do, but when I try to install it, I get “Metadata Definition Not Found”.

Any advice would be appreciated.