When you are done and ready to hand in your final movie.
Make sure you don't have any extra clips in the timeline.
Click on the Export tab.
Give your video a File Name.
Set the location where you want to save the final video.
Use the preset High Quality 1080p HD.
Change the format to H.264.
Make sure the Range says Entire Source.
Click the big Export button at the bottom and wait.
Test your video once complete. Double-click the file to play and select Windows Media Player or VLC.