There are plenty of applications created to cut and join videos. The simplest way to do it is through the database of Software Informer or Mac Informer. Access the page (Mac results)and download an application then load your movie. Everything should be straight forward afterwards. Simply load the movie, mark the cut time and then mark the end time and save the portion of the video to your hard drive. To join two videos, simply load the videos, select the JOIN feature and save the output.