When the demo starts, press W repeatedly to select Mars and use the arrow keys to orientate the cruiser until you see the red rectangles pointing the way to Mars. The press Shift+1 to start movement (or press Shift+9 for max speed). As soon as you approach Mars, press 0 to slow down to a stop.
Once in Mars' orbit, press Alt+1 to launch an Interceptor. You need to enter the planet's orbit. Shift+1 starts your flight - go right towards the planet. For other instructions and hints, please read the electronic manual.