The main screen is a list (a UITableView) of people and how much they owe you overall. If a new person owes you money, you click an 'add' button to enter them into the list. The first time you add a person on the list, it asks for the name, amount, and description and also if it's a 'lend' or 'borrow'. Once you have that person on the main list, the next time you lend him money again or he pays you, you can click on that name and enter the amount that he paid. This becomes a rolling sum. The tutorial pictures will explain better.