It takes about five minutes: install the app, link the screen with a code and pick a playlist.
What you need
A TV with an HDMI port and an Android TV box, or a TV that runs Android TV, a Wi-Fi or cable connection and a Clouty account.
Steps
On the TV open Google Play and search for Clouty TV. If it is not offered for your device, download the app from clouty.app/tv.apk and install it, allowing installs from that source when asked.
Open the app. The screen shows a 6-character code.
In Clouty open My screens, add a screen and type the code into that screen's field. The TV starts playing at once.
Choose a playlist for the screen. A new free screen starts with a welcome slide until you do.
Keep it running
Long-press OK on the remote, or press Menu, to open the app settings. Switch on autostart so the screen starts by itself when the power returns, and allow Display over other apps if the TV asks.
If something is wrong
No picture: check the Wi-Fi, then press Reload on the screen's card in Clouty. The app keeps playing the last playlist when the connection drops.