Start PowerPoint:
- Insert video clip into slide by selecting the "Insert" ribbon, choose "Video" from the top right hand side of the menu and click on "Video on my PC"
- Select video and click on "Playback" ribbon at the top of the screen
- Click on "Trim Video" button at the top left hand side of the menu
- Use the green/red markers to indicate where the new start/end of the video are - or specify the actual times in the prompted fields via mm:ss
- Click on OK
