File Management: Movies are often huge files. Movies contain duplicates of the movie clips from cameras or phones.
- Create a folder on the desktop named after your movie project e.g. "2020-12-31 Boys Trampoline"
- Copy into this folder all "source" files (movie clips, still photos and audio files) that you want to use in your movie.
If you don't want to keep an editable version of the movie project, then delete the movie clips after you copy them to the folder so that the new finished movie will replace them in your "Photos" app.
(Yes I know iMovie will connect to the "Photos" and "Music" apps automatically, but, if you wish to archive an editable version of the project, we cannot rely on the same track existing in your "Music" app, or the same photo remaining in your "Photos" app.)
- Open iMovie - File - Open Library - New