Get it and put it on top of the other paper with the peculiar design. Now you have the map to the hedge maze. Somewhere in the house you'll find a match. Open the compartment and get the mask. Do not push red button.
Black button kills tanks and white button destroys planes.
Next you'll encounter the rocket. After the truck launches the rocket, push green button then push black button. Move east again. Now Save game if you are in the Park but have not yet destroyed the monument. Blue I think will get the diamond from the monument.