To trim your video:
Select the video on the canvas.
Click Trim from the right-hand side menu.
A timeline will display on screen that allows you to trim your video clip as desired.
You have the option to trim the video on both sides, as well as being able to split the video in to sections, using the Split at time option.
When you have finished trimming your video, click Done and the trimmed version of the video will be saved and applied to the final version of the project.
Notes:
You can zoom in and out of the timeline, to ensure you can trim correctly