Hi,
You can either edit your clips in QuickTime Player before putting them into iMovie (or wherever you want to store them), or edit them in iMovie.
To edit in iMovie, import your clips into iMovie. Then do a Modify/Split Clip at the points you want, and delete the segment in between to remove the unwanted footage. You can trim the remaining footage to fine tune the splits. Then you need to share out the remaining footage as a File to your desktop. This is because that due to iMovie's non-destructive editing, clip segments that are deleted are not really deleted -- they are just made invisible in the project. The "deleted" footage, with its gigabytes, remains in the iMovie Library Original Media folder in the Finder. However, when you share out the project all of the invisible "deleted" portions of your clips will get left behind. Then, in iMovie, you will need to delete the project. When you do that, the clips in the project will be automatically placed into an Event bearing the project's name. You must delete that Event, not just the clips in it, in order to permanently remove the clips from the system. That will leave you with an independent movie that contains your 2-3 10 second clips. You can store the shared out movies in a folder on your Finder for use in your final iMovie project. If you want to do more splitting and cutting, you can drag the movie back into a newly created iMovie project.
You also can edit the clips in QuickTime Player before putting them into iMovie. That would permanently get rid of the deleted segments and their gigabytes. To edit in QuickTime Player, import the clips to your desktop and then open them in QuickTime Player. Do a View/Show Clips. Then move the vertical red playhead from the left side to the point where you want to make a split. Do Edit/Split Clip, and delete the unwanted segments between the splits. You can also do Edit/Trim. When you are done, share out the movie to your desktop folder where you are collecting your saved segments for use in your final iMovie project.
-- Rich
