Beyond the basic layout of the factory floor and buying new and faster stations for performing steps in the process you would deal with suppliers, choosing how much stock to have on hand of raw material and when to order more. Do you want to make some products before you get orders to ship out right away or only start building once you get orders? How will you make sure your workers are busy? Do you want to pay extra to run the factory over the weekend? As the cars are made you get to watch them progress through the factory and watch the employees build each part or mill around if they have nothing to do.
The game similar to many sim games starts you off in a massive warehouse where your first production line only takes up a very small portion of. As you would grow the primary interface would be managing the layout of the factory floor and its growth, but just like controlling the elevators in sim tower, how you managed the employees and the way orders were fulfilled would determine your success at fulfilling orders, generating more revenue and ultimately the size your factory could grow.