When using separate devices we try to keep things in sync but for video, it's unlikely it will be perfectly in sync as each device uses its system clock and there can be slightly variable time for videos to start playing.

However, the first thing you need to do to keep two screens in sync is to apply content using Channels and to then set your screens Playback Mode setting to Sync, an option described in our article Synchronizing Screens with Playback Modes: Sync and Unsync. First, you add your content or media to a playlist, then assign the playlist into a Channel to schedule your digital signage content. Then, you can simply assign your Channel(s) to any desired screens to keep your content in sync with each other by ensuring the Sync option is selected.

If you are using Signage, set your content or playlists within your Schedule.