How do I move (drag and drop) the video files or import them into iMovie?
Only edit compatible files can be "drag 'n dropped" to any of the newer iMovie apps. (I.e., edit compatible viles can be drag and dropped directly from a "Finder" window or desktop to a named event within the open application. They can also dragged and dropped directly from a "Finder" window or the desktop to an iMovie "Event" folder with the application closed and automatically be recognized/thumbnailed then next time you open the iMovie app.
Non-edit compatible camcorder compression formats still on the camcorder must be imported using the "Import from Camera" option if you want iMovie to automatically convert them to an edit compatible compression format during the import process. Non-edit compatible files already copied to your hard drive normally have to be manually converted to an edit compatible compression format by the user before than can be file or "drag 'n drop" imported to the app as described above.
like above how do you move the video files, rename, import to imovie for it will only allow you to open them, and view the video in quicktime, or cancel.
As to the renaming of files, you can do that at the finder level or use a utility app to modify the name (and/or file date which governs the ordering of named files) but you are cautioned to do so before importation as doing so after import can "orphan" file references within the iMovie app. The same holds true for the moving of event/project files or folders. Only move them from within the iMovie app as moving them manually at the finder level externally can "orphan" the references within the iMovie app data base.