A computer! Either a desktop or laptop will do. Windows, Mac or Linux is fine -- and don't worry if it's an older model.
Some rudimentary computer skills. You need to know how to use a mouse, as well as how to open and save files.
Some basic math comprehension. You need to understand addition, subtraction, multiplication, and division. Just basic grade school stuff. (And don't worry, you won't have to do any of it in your head!)
Some kind of spreadsheet software. You may already have Microsoft Excel, and that will do just fine. If not, you can download and install a free program called LibreOffice (available for Windows, Mac, and Linux). (I'll talk more about this in the next lecture too.)