How do you build a store on the second floor in mall tycoon 3?

To build a store on the second floor in Mall Tycoon 3, first ensure that you have unlocked the second floor option by meeting the necessary requirements. Then, select the "Build" menu, choose the type of store you want to create, and click on the designated area on the second floor. You may need to add escalators or elevators to connect the first and second floors for customer access. Finally, customize your store's layout and design as desired before finalizing the construction.