OK, Bare with me LOL this is so simple! If you have the Windows Movie Maker....
1. Open the program and make sure the "Task Pane" is open. If not go up to "View" and click "Task Pane"
2. Once that is done click the link on the side of the page that says "Import audio/sounds".
3. Find Walts speech on your computer and upload it.
4. Once uploaded drag the speech to the bottom of the maker where theres a big blue timeline that says "Drag Media to the timeline to begin making a movie"
5. Once you do that you click on the speech in the timeline and at either end of the "SONG/AUDIO" there will be a red line/arrow of some sort which you click and drag from side to side to shorten the clip to however long you want it.
6. Once you have done that and are satisfied with your work, go back to the side of the page to the "Task Pane" and "Save to your computer".
You should then be ready to roll!