Here is my guided video, but for those who want a verbal walkthrough:
1. Load the first campaign area: IPSILON.
2. Load the first mission.
*You may have to beat it the regular way the first time.*
3. Delete everything by pressing x while hovering over the item, except the middle grey cube.
4. Use on of the top buttons to "set the machine on the ground".
5. Add a cannon to the top of the cube.
6. Press the space bar to start.
7. Press C to shoot the cannon at the house.
You'll destroy the house with 2 items.