Q: Moving and Storing iMovie Files

Dear Community,

My iMovie files are taking up way much to much room on my Mac, and I want to store them on an external HD. But unlike the old versions where you could move the "Events" elsewhere, it seems very hard to move and delete fils in the newest version.  Even if I "Move Clips" a library located in an External HD and see them there, they still seem to stay on my Mac, even if I delete them. Does anyone know how to move and copy files and delete them off the Mac?

Thanks, John