Your first step might be to go for a car factory to get a tiny glimpse of what goes intro making one. Then think about how you are going to source all those parts. Then how much all of this is going to cost. Then figure how many years it will take to start turning a profit. Then multiply your yearly operational cost by the number of years you don’t make a profit to see how much capital you will need to start with. (Hint- that’s where the $500,000,000 comes from.)