1) Tap the menu on the video player screen and then select the trim option.
2) You can adjust the start or end frames to trim the video. To do this, grab one of the ends (it will turn yellow once selected) and drag to your desired position. Use the blue play button to preview your trimmed video. Once you are satisfied press Save.
3) You have the option to save the trimmed video over the existing file, or save it as a new file. If you wish to make multiple clips from one video you can do this by trimming and saving as a new file as many times as you want.