You need to write code for the car, or download some sample code. Then write a function that lets your model running the plbiped01 code enter a car. From there onwards, the code will actually control the car, not the plbiped01. The model will simply sit in the car model. Your question is much too generic and shows you need to learn some basic programming (probably also outside of gamestudio) to have a better idea of what exactly you're doing