Garage code How do you program your garage code in a 1998 mercedes c230

In my Audi, and in my mother's Avalon, you choose which of the buttons on the visor you want to use, hold it down, and while holding it, you aim your garage door opener at the visor and press the button. This allows the car's memory to scan the code that the opener sends, and programs it into the car's opener for the selected button.