If anyone still struggling to import the files to C3, first make sure you tick all of this in File > Other file actions > Custom Save Options > and hit apply
After that make sure the entity name is not a generated one entity_000, and rename it to what you want, ie Player
And then you can Save Project As > .scon not .scml (Make sure the file name is the same as the entity name. (Note. if you already had the same .scon file, don't overwrite it, delete it first.)
And to zip it, you need to select all of the files not with the scml, and then right-click on the .scon file (IMPORTANT) and you can start .zip from there.
After that, open your C3, open the layout for importing this, and make sure the layout is already connected with the event sheet (IMPORTANT). And just drag and drop the zip file into the layout canvas, and don't do anything until it's done. (Note. if you already had the same animation before, you need to delete the former event before importing a new one)