How does the Audi A8's Mild Hybrid Electric Vehicle (MHEV) technology work?

I'm trying to understand how the Audi A8's MHEV technology operates. Specifically, how does it incorporate a 48-volt electrical system and regenerate energy during braking?

The Audi A8's MHEV technology uses a 48-volt electrical system to power a belt alternator starter (BAS) that assists the engine with starting, stopping, and acceleration. When the car brakes, the kinetic energy is captured and converted into electricity, which is then stored in a lithium-ion battery. This energy can then be used to power the car's electrical components, reducing reliance on the engine.