How does the Audi A6's Quattro system distribute torque?

I've heard about the Audi A6's Quattro system and how it helps with handling, but I'm not sure how it actually works. Can someone explain the details?

The Quattro system in an Audi A6 utilizes a center differential to distribute torque between the front and rear wheels, giving the car improved traction and stability. If you want to optimize performance and power, the ideal torque distribution should be 40% front and 60% rear.

In off-road situations, the A6's Quattro system can distribute up to 70% of the torque to the front wheels, providing superior grip and control on uneven terrain. This can be especially useful in inclement weather conditions as well.