I will explain it by saying y axis represents the length of the car while x axis will represent width of the car.

Refer to numbers on diagram according to explanation.

The servo horn (#1)transfers rotational motion in to push/pull motion. This is along the y axis. Then it comes to a transfer point (#2) where it will turn y axis motion in to x axis motion. The servo saver is usually** located here. The bell crank shaft transfers this motion to the other bell crank on the right side. The tie rods transfer the x axis push/pull motion in to rotational motion via the hub. (#3). This is how the tires(#4 LOL) get the rotational motion to turn the car from the rotational motion of the servo.

It doesn't get any more clear than this. Steering systems do vary over different cars but this will demonstrate the main idea of how it works.

Ryan