When you start you are starting near the crane, if you are starting backwards don't go front you go back ,if you are starting from the front side you go front.then turn right.then there is a door on the left side.shoot it.
It will open, go in.
When a noise come.you go out.only if you here the noise once, if you hear twice,then go out and go in again.you have to hear the noise once.
Then see the crane, it is moving.
NOTE:do not go in front of the crane to hit you,you might get hurt to much.let it reach till the place where you go to get weapons in the sky.
Tell your friend to see the rocket on the crane.
Then you go to the place where you put the crane on, go in and come out.again you must hear one time the noise.
Tell your friend to see the rocket.the rocket has disappeared, thats because it has blasted off.