Car Repurchase – Payment ?!?!

Hello people Have a question, how do you actually pay for a brand new car that you ordered/purchased in the car dealership? Is this already paid at the order or only when you get the vehicle papers, or only when you first registered and picked up? Will the vehicle be paid for or by bank transfer? Would I really be interested in buying a new car if I had only used and paid in cash. Would I be happy about feedback and lively answers vg and thx