Have you tried sideloading it?
If not you'd copy the apk. file from their website onto a USB. Install a file manager onto the tv from the playstore like TV file commander. Use that to sideload the. Apk from the USB inserted into the tv
It may or may not work as looks like its only designed for phones.
If it doesn't work it looks like you can cast from your phone to the tv with the premium version of the app
