I know that there are different programs for video editing and many of them are paid, but I use this free software https://www.freemake.com/free_dvd_burning_software/ to edit videos, download videos from the Internet or burn video to disk or ISO. Also, this video editing tool can be used as a converter in order to change the video extension to any. Sometimes it helps to improve the quality of the video. I think this is the best solution for a beginner to start editing videos or make changes. If you need additional functions, then you can look for some other software for more professional editing of such files, but I believe that for a beginner in this tool for video files will be enough.