When an entity offers valet parking, you drive up and hand your keys over to the valet. You would continue on to the event or establishment after receiving a claim ticket whilst the valet drives your car around to a typically separate parking area. There they park and secure your vehicle until it is time for you to leave.
When it is time for you to leave, you hand your ticket over to the valet, who retrieves the keys and your vehicle.
While this is normally a safe and transparent process, there are always inherent dangers. Sometimes the valet has an accident that destroys the car, scratches the paint, or puts a nice-sized ding your Bentley. If you have a rare racing vehicle, there have been instances where the valet has gone on a joy ride. A famous fictional example occurs in the movie Ferris Bueller's Day Off.
Because this is a service, it is customary to tip the valet.
Iron Noder 2017