Event driven media play on Android TV in museum?

The desired use case:
In a museum, a standard android TV is playing/looping video file A.
We want to start a different video (B or C) upon occurrence of a trigger and at the end of the clip the original movie should restart and loop.
This should be feasible using HA media player actions in an simple automation. I can switch on/off the TV from the automation and a “casting” symbol appears om the TV screen but i do not see the media file (avi for test) appeear.

  1. should the media be stored locally or can it be on a network?
  2. Where should the media clip be stored and how could i reference the specific file in the automation action play_media?

Please advise.