VLC desktop 3.0 documentation · Primary-source explanation; examples are illustrative. Instructions are based on publisher guidance; a UK IPTV account was not tested on this platform.
Choose the intended playback arrangement
VideoLAN desktop 3.0 documentation describes opening a video through Open Multiple Files, showing more options and choosing Play another media synchronously to supply companion audio. This is useful when an authorised narration or alternate recording is stored separately. First confirm that the companion belongs to the same edit and duration. A file with a plausible name can still contain a different introduction or missing section.
Select the companion deliberately
For an original example, use a permitted silent demonstration video and its separately supplied narration. Add the video as the main media, then browse to the companion in the synchronous media control. If the main video already has sound, inspect the available audio tracks and select the intended companion rather than assuming its sound has replaced the original automatically. Check an identifiable event near the beginning and another later in the clip to review alignment.
Decide whether a portable output is needed
Opening the two sources together does not by itself establish that a new combined media file has been created. Keep both originals available for this playback arrangement. If the goal is a single file for another player, use an appropriate documented muxing or export workflow, then inspect that output independently for tracks and timing. The distinction prevents a successful local preview being mistaken for a completed handover, especially when the second computer cannot access the companion file.