Presumably that includes the price of the new car and accessories, less the value the dealer places on your trade-in. You are faced with financing the difference between the price on the new car and the value you accept for your old one plus, of course, local taxes, title and insurance. You will finance at local market rates unless the manufacturer is offering a finance deal. You make the payments for the specified number of months and you own the car. Then you start all over again.
Many people start all over again before they own the car.
Finance companies loooove them. All that is the value of the lease. Whatever the number he gets, that's what he's going to divide by 48 months and quote you as your monthly lease payment. Because you are basically renting the car only for the period that you use it and not for its entire life as when you buy it. Probably the manufacturer has also financed it for a lower interest rate than your bank charges just to get the car sold.