First of all, the movie you watched is from 1.2.5 and most likely outdated. Go to your MC launcher -> options -> force update -> start MC.
Then download the latest version from the link below.
Then follow these instructions:
1. Go to the minecraft bin directory and backup minecraft.jar
2. Using 7zip or equally capable ZIP viewer open minecraft.jar
3. Delete the META-INF folder
4. Copy the "com" directory contained within the mod to minecraft.jar, replacing the existing one.
Note: The SPCInstall.JAR can be opened up the same way as Minecraft.jar and you can install the mod manually by dragging the files from there into Minecraft.jar as you usually would.
5. Close minecraft.jar
6. Copy ALL the ".jar" files, ie: WorldEdit.jar contained within the mod to the minecraft/bin directory (the same directory as minecraft.jar)