Moving Media

I thought I understood how media is managed within iMovie, however, I clearly do not!

I was revisiting a project I made a few years. For simplicity lets say I have 2 events in the sidebar - France and Skiing.

If I click on the Skiing event it shows 20 clips, however, if I click on one of the clips and select Reveal in Finder, the actual clip is within a folder that sits within the France folder. I would have thought that when clicking on an Event the clips shown would be within the Finder folder with the same name?

If I click on the event France it doesn't show any clips.

How do I tidy things up so that the clips shown in the Event Skiing are actually in the Finder folder Skiing. I guess I could delete and reimport them but they are linked to a project.

I know it probably doesn't matter where they are stored but I just want to understand how these things are managed.

Many thanks