To edit a previous project, open the software and browse to the .hue file saved on your computer using the 'Open a Saved Project' button.
If you have exported your film already as a .mov file, you will have to find and open the corresponding .hue file to make changes. By default, your saves from all of your old animation projects will be in a folder within your computer's Documents folder. The exported version of a movie is not directly editable in HUE Animation Studio (though it can be imported through the File menu and split into frames that way).
Please note that if you are using an older version of the software, the save files will be called .sam files instead. You can rename the old files so that the name ends in .hue in order to open them using the newer software.
We recommend retaining a backup copy of your original movie, as you never know when you might want to make improvements in future. Ideally, it's best to back up the entire HUE Animation folder from time to time to ensure that all of your images and sounds are safe.