How do I set the weapon up


Hint 1 of 7:
First you need to assemble the catapult.

Hint 2 of 7:
GET CATAPULT ARM  and then USE CATAPULT ARM WITH CATAPULT.  +2

Hint 3 of 7:
Lower the arm for firing. MOVE LEVER on left side.     +1

Hint 4 of 7:
You must be in front of the catapult to move the lever.

Hint 5 of 7:
You need a missile for the catapult. GET ROCK in front of door. +1 

Hint 6 of 7:
USE ROCK ON CATAPULT. When guard comes out, MOVE LEVER.  +11

Hint 7 of 7:
Rock lands where guard pauses after walking through door.