Where to begin?!

1. This is the picture of a catapult (Fig-1, 2):
image
Figure-1:

image
Figure-2:

2. With reference to the diagrams of Step-1, will you please explain the meanings of?:
(1) Rotating the catapul,
(2) Tilting the catapult, and
(3) Pulling back the arm of catapult.