As we have had a couple of enquiries via FMS Enquiries about audio and video, we have added some information to the FMS Community on how to edit using VLC Media Player. VLC media Player is a free application which allows you to play and convert videos. You can save in many different formats.
You may be looking to add new audio to an existing video, or remove audio before commencing adding a new narration. For example a demonstration of a practical session in a laboratory, or a tour around a building. You can also extract audio only from a video.
See the guide on how to do this here: https://ncl.instructure.com/courses/30988/pages/editing-with-vlc-media-player