Hi, ann,
It's true that Samsung is not listed on Apple's website of iMovie supported camcorders. However, that doesn't necessarily mean that it won't work with iMovie. I believe that Samsung records in H.264 codec that iMovie supports. If you haven't already, you should try it with iMovie.
If iMovie doesn't recognize the Samsung when you plug it in, try importing instead into the Photos app on your Mac, and from there you can access your vid from the Photos Library item in the iMovie media view sidebar. Another way is to import to your desktop using the Image Capture app on your Mac, and then drag the movie from your desktop into iMovie.
In the event that iMovie has trouble processing the format of the video, try using the free download, Handbrake, to convert the video to Mp4/AAC, that Handbrake will do by default. Then you should be able to edit it in iMovie with no problem.
-- Rich