SC on Android TV or Google TV

Unlike on Android's mobile or tablet, which I'd recommend Findroid as a client - for Android TV or Google TV, I'd suggest using the official Jellyfin for TV app "Jellyfin for Android TV" from Google Playstore (for now).

Enter the address of the server, add your account.

Bear in mind that you may have to change the player client within the app itself to either LibVLC (uses VLC's libraries) (read below) or just another external player of your choosing. Also, the official Jellyfin app for Android TV & mobile/tablet are different, make sure you get the right one.

UPDATE: The app doesn't use LibVLC anymore due to security reasons.
Therefore, if your Android TV or Google TV device can't play certain media due to codec-support restriction, install any media app such as VLC and set VLC it as the default external player within the Jellyfin app.
Newer models of Android TV / Google TV usually supports these codecs anyway, they paid the license/royalty for these codecs.

..and that's it, really!